So, as many people here are, I am new to bicycle commuting. Just trying to see if there are any good ideas out there.

Do most of you change clothes once you get to work? I'm guessing it will become more difficult for me to bike into work with the same clothes I work in once it gets warmer. There is a fitness club near my work. I had considered joining, just for the showers.

Also, what should I keep in an emergency/gear bag? I'm thinking I need some type of bag that attaches to the bike, as my messenger style bag was really difficult to ride with when I tried.

The most useful piece of advice I have for you, if (like me) you'll keep your work clothes in a locker at work and change when you arrive:

NEVER, ever take any item of clothing home until you bring the new one in. ESPECIALLY PANTS.

As for the emergency/gear bag, I bring my lunch in every day in a regular backpack, and in that bag I have the basics: phone, keys, wallet. I keep my "bike gear" in my saddle bag--tube, patch kit, CO2 cartridge and inflator, multitool. For a little extra peace of mind I put one of those Hi-Viz running vests around my backpack, since the backpack covers my Hi-Viz jerseys.

I also ride with a RoadID on my wrist.

I carry my work clothes and lunch in a messenger bag. It doesn't move around and doesn't bother me. I have a pair of dress shoes at work so I don't have to carry those and the only other shoes in the equation are on my feet. I sometimes have some gym clothes in there also because I like to workout and run after work before riding home.

I have an underseat bag for extra tube, allen wrench set and repair kit that just stays on the bike

Picture linked below b/c it's big for the forum
Link to picture of my Marsee bag

I'm lucky to have a locker room, so I bring in clothes once a week. I rotate dress pants. Shoes, ties, and a blazer stay at the office.

I keep spare underwear and socks in my desk drawer at work. It has saved me more than once when I forgot to pack things the night before.

Being that I am the janitor, I don't work in close proximity to the rest of my coworkers. I only have a six mile commute, so I can get by with the sponge bath in the toilet stall thing.

I carry just about anything I even think I might want or need, mostly because of my military training. I would lot rather have it and not need it, than need it and not have it.

I keep shoes, belts, towel, SPARE towel, toiletries at work. (We have showers and lockers available at work - lucky me!). Daily change of clothes in backpack or pannier depending on which bike. I live close enough I could ride in street clothes if I took it really easy but prefer cycling clothes and not worrying about sweat or road grime.

Keep bike in good repair and be able to repair anything likely to break that would keep you from getting to work or back home. For me, that means being able to repair two flats (plus I carry a patch kit) and re-inflate the tire (RoadMorph pump), minor adjustments (multi tool). I carry ID and cell phone (more for wife to communicate "please pick up $ITEM on way home"). I have a reflector (DMV compliance), bell, and lights semi-permanently mounted; this time of year is more useful for fog/rain than darkness.

I keep a spare tube or 2 at work and in winter extra batteries for backup lights (primaries are Li-Ion, backups use AA or AAA). Also some extra gear in winter in case I get really soaked riding in and need at least a dry base layer.

I have a locker I could use, but no showers. My commute is a flat 7 miles, and in cool mornings it's not a sweaty ride.

Another thing I haven't thought of... lights/reflectors. I don't have any right now. Most of my ride is on a trail and none of it is on busy streets.

I commute self-contained. Ortlieb panniers having clothes, belt and shoes in one side and laptop and lunch in the other. Tools, spare tube, wallet and other miscellanea spread between the two.

+1 - I used to bring in clothes every day, but it's a lot more pleasant to ride without a backpack (and I'm not opting for saddlebags any time soon).

I bring in my clean clothes on Monday or Tuesday as I usually ride on Wed, Thurs and Friday.

I'm spoiled, we have full shower facilities & a gym on site. I keep a change of clothes at work along with shower gear (towel, soap, flip flops for shower floor, etc.). I keep my lock attached to the rack @ work (lugging it back and forth SUCKS). For my laptop, I have a spare charger that I keep at home so that is one less thing to haul back and forth.

Recently I moved and cut my commute down by about 16 miles (9mi each way to <1mi each way). When I was doing the longer commute I would wear full cycling gear, carry everything in a pannier, use good lighting, etc. Now I just bring rain gear & can hammer it all the way to work with minimal sweating. If I plan on a long ride home I'll bring bike specific clothing, otherwise I wear my office clothes (which are casual).

Oh yes, I also wear my RoadID.

A rack an panniers is probably the best combination for commuting. However, depending on your bike, it's not always a viable solution (no braze-ons for rack, short chain stays so your feet hit the panniers.) Saddle bags are nice. I prefer the carradice SQR saddle bags. They attach to a seat post mount. The bag is very simple to attach to the mount and to remove from the mount. There are many options in saddle bags from carradice. The link below shows many of them. The SQR bags are about half way down the web page.

https://www.peterwhitecycles.com/carradice.asp

Do most of you change clothes once you get to work?
Yes. I used to have a 7 mile commute. There was no shower there, so I showered at home, then cleaned up and changed when I got to work. I changed, put on deodorant and used baby powder (some people use baby wipes to freshen up). Then I went to the bathroom and cleaned up my face and rinsed out my hair if it needed it. Now my one-way commute is 17 miles, but now I have a shower to use, which is nice.

I'm guessing it will become more difficult for me to bike into work with the same clothes I work in once it gets warmer. There is a fitness club near my work. I had considered joining, just for the showers.
Maybe, maybe not. When I did 7 miles, I was okay without a shower (see above), and I'm in Texas.

Also, what should I keep in an emergency/gear bag? I'm thinking I need some type of bag that attaches to the bike, as my messenger style bag was really difficult to ride with when I tried.
I put a rack and panniers on my bike. With two panniers you can carry a boatload of stuff. Typically I carry:
. Repair stuff in a small saddle bag (a tube and stuff to change it, plus a multitool)
. In my left pannier: Work clothes, towel for the shower, lock.
. In my right pannier: Lunch, toiletries, clothes for the ride home (usually just a fresh t-shirt), windbreaker or whatever (depending on afternoon weather forecast)

Every time I commute, I pack the "expendables" (clothes and lunch); the rest of the stuff stays in the panniers all the time.

I have a good headlight and two blinkies on the rear, running day and night. I try to carry my wallet, cell phone, keys and work badge on my person but if I don't have pockets I try to have at least my cell phone handy.

With my new commute I can (well, I'm not supposed to but I do) leave stuff in the locker room where the shower is, so I hang up my shorts in a locker. I wear a pair of Target cycling undies under them for the ride in, so they're usually not too rank when I get to work. They are dry enough to wear home.

You guys that stash clothes at work amaze me. That seems like complicated logistics, but you do what works best for you.

Like Doohickie I use a rear rack with panniers. I have a touring bike because my commute is 18.5 miles one way. I am among the fortunate with a locker room and showers at work. In fact, I dreamed of commuting for YEARS but couldn't do it without a shower. My company finally moved to a new building with a gym and locker room and my last excuse for not cycling to work was gone. Ride a bicycle in Florida in August and you understand why a shower is not a nice-to-have, it is a requirement.

One pannier holds my laptop, towel and hangars (to hang up my soaking wet bike clothes so I can put them on dry at 5 o'clock) and my lunch. The other pannier holds my work clothes, soap, and deoderant. Under my saddle I have a small bag with a spare tube and CO2, a park tool and a couple of tire levers.

There is a bike rack in our parking garage which can hold up to FOUR bicycles. Mine is the only bike ever parked in it.

I keep repair items (tube, tire levers, multi-tool, patch kit, etc) in a small saddle bag that's always on the bike. For stuff I bring to work (change of clothes, laptop, lunch), I've used at various times a backpack, panniers, and a messenger bag. They all have their pros and cons, but all are workable depending on how much stuff, the distance and a few other things.

Since you mentioned a messenger bag, I personally need to have a cross strap in order to have them work for me. Otherwise they swing all over the place. Likewise, I like a backpack with a waist strap at least. In general, I've found that with any of the carrying options, spending a little extra money for at least a mid-range product was well worth it.

I don't keep clothes at work except for shoes. But I do keep other stuff their like soap, conditioner, etc. I also keep a towel at work but that gets exchanged regularly. I try to limit the amount of stuff I carry back and forth each day.

Most experienced commuters use a rack with one pannier bag. It doesn't affect the balance of the bike and is easier to manage than two.
A modern quick-release mounting on the pannier is better than a slow or fiddly one.
A basic repair kit should include a puncture kit+spare inner tube.
I keep a few essential at work (underwear, socks, shirt) so if I forget them I can still show my face. I also keep a couple of bike spares, including an extra inner tube.

Tools in saddle bag. Emergency clothes in drawer, used them once in 4 years of commuting. Keep extra shoes at work so I don't have to carry them. Today's clothes, lunch, possible rain gear in pannier. We have showers, but that will end this year, then it will be bathroom washup. 13mile commute is too far to go without cleanup and change.

Pannier is also good for groceries on the way home, that gallon of milk makes the last hill more interesting.

install a rack and get a rack trunk
carry stuff to fix a flat: tube; patch kit; tire levers; pump
I change clothes at work. I have a shower now but didn't always.
you can stock pile food and clothes at work.
arrive before anyone else so you have some privacy
start small like by changing socks; underwear and under shirt.
then work your way up as it gets hotter to doing a simple sink type washcloth wipe down (bring a washcloth and hand towel)
for soap I like diluted neutrogena shampoo cuz it rinses well well used diluted and has virtually no fragrance.
with a cup you can do your hair head and face in the sick. the cup is for rinsing

party on Garth

Wonder if this depends on what part of the world/region you're in. It would be hard for me say what most people use based on what I see. If I had to pick, I'd lean towards backpack. That's not a recommendation. I think people use them because that's what they have. I also see plenty of panniers too but I see as many with two as with one and overall I'd say panniers are still in the minority.

I couldn't get by with one pannier unless it was pretty huge. Combined the panniers I have are about 2600 cubic inches but I feel like I can't get as much in them as I can my 2100 cubic inch messenger bag.

I run a flashing PB Blaze 1W in front and a PB Superflash in the back whenever I'm riding then have a brighter headlight for commuting in the dark. I would suggest that you get some form of "be seen" lighting.

Like many here, I leave my shoes, belt and most of my work keys (when you are in facilities, you have a lot of keys) as well as a spare towel in my office. My panniers carry my clothes, towel and other assorted necessities. Seat pack carries the tools, tube and patch kit.

I have a short bike commute, 1.72 miles to the train. I can usually get by, even in the summer without changing or bathing. Even so, I have a shower & locker at work, so I can't help you directly.

Lots of folks who don't have a shower at work have mentioned that the trick is to shower in the morning before you go, which means your sweat won't smell as bad when you get there. (bacteria makes it smell worse) Then, they bring baby wipes and deodorant to work and clean up in a toilet stall or one-hole bathroom.

Search this forum for 'shower' and I bet you'll hit paydirt. I remember a few such threads just from the last couple weeks.

I have several pairs of shoes at work, plus t-shirt and a few tops, plus a jacket. I take jeans and t-shirt, sometimes another top, to work. I also keep socks, track pump, couple of cycling outfits at work.

I shower at work, keep my toiletries there too.

I should keep my bike repair stuff in the saddle bag + frame bag, but they both tore so these days it gets transported in my ruck sack. I'll have to buy new bags this week to get some weight off my back.

Come to think of it, I also keep lube and cleaning liquids for my bike at work too! On the odd lunch tie I'll clean the bike up. This thread has got me thinking of what else I could store at work...

sounds like I'm one of few who actually rides in work clothes (business casual). A little over 7 miles. As the OP writes, it works great except for summer (or morning temperatures in the high sixties). I am lucky then also, because our company has a special (casual) dress policy during the summer months, so I always have a couple of jeans at work and bring with me fresh underwear and t-shirt.