Commuting over the years
I've been bike commuting to various work locations for over 30 years. The typical rt distance is 15 miles. What I've found helpful:
1. Some kind of topo map of the route to reduce hills. (I used MS Terra Server or google earth) There is always a flatter way and the goal of my commutes is just that, commute, not ego.
2. I like the Specialized armadillo tires as the most flat resistant and also use a slime tube. Yes, I know, weight on tires is higher but think about it, if you are commuting, you typically have to take lots of things like a briefcase, etc to work so I don't think too much about weight, more about how much fun a flat is.
3. I've tried panniers, special rack mounted briefcases but oddly, I have found a simple wire basket mounted to my rear rack the best for me. It carries the briefcase and if I stop at the market, it carries odd shaped items better as long as I have a bungee cord.
4. Lights. More to be seen than to see. I actually got stopped by a policeman for not having a front light once.
5. Helmets and gloves. Once you fall, you know why gloves are nice.
6. Ok, this is out of the box. I've commuted on MTB, Comfort, Flat handlebar road but never exotic stuff, always < $1000.00, but here is my favorite and why: Giant Revive with an electric motor inline with the gears (Cyclone-tw.com has the double freewheel motor kit). **All the things we don't like on a daily basis, starting from a dead stop, hills, headwind, sidewind, all of the above combined, become irrelevant on an ebike. That makes it much more likely that you will commute and save carbon. Also, the average speed maintainable without sweating is probably around 18-20 mph which makes for a faster commute. And lastly, as I move through the 50's, I can see a time when a conventional bike won't be rideable with older legs but an ebike will extend that joy of riding for a few more years!