ShadowGray

Yeah, so my set up was that I had one of those small clippable tailights on my saddle pack. While going over a slight bump I hear a crash behind me, looked behind to see my tailight on the ground. I get on the sidewalk to wait out the light so I could go into the street and pick it up. Then next thing I know, this little red mini cooper happens to drive RIGHT on it, and the next thing I knew my light was in 100 pieces. Good thing I got out before dark, didn't really need the light, but still so pissed! That was a good $5 light! Now I have to get another one!!!

vaticdart

I always carry three. One is permanently on my seat bag, and the other two live in my mess bag. Two Superflashes and one Mars 2.0. When it's dark, rainy or foggy I clip one to the back of my mess bag and one to the bottom (I ride in the drops). I also carry some extra batteries.

I've had blinkies randomly fail on me in the rain plus they can pop off, you can wipe out, crash, or otherwise subject them to stresses they're not really designed for. Good to have extra.

Machka 

I own about 15 taillights. 2 are on my bicycle, 1 is usually in my handlebar bag ... and the other dozen or so are in a box on the shelf.

Russ

I carry two lights, but both of them are mounted and on. I figure if I'm going to haul one around, I might as well use it.

ItsJustMe

I keep two on the bike, a PB Superflash, and a Cateye TL-LD1000. The superflash is the only one I usually run except in the dead of night. It could come off I suppose but never has. The Cateye is screwed directly to a metal L bracket on the rack; I'd have to get hit by a car to break it off.

DataJunkie

Just one right now. I only need it for 15 min.
When I ride in the dark more I carry a second one. If both fail then onto the sidewalk I go...very slowly.

daredevil

One on me (clipped on the back helmet strap), one on the bike.

freako

I don't bother with carrying a spare tailight since I feel that would be a waste of space for something that would never be used! But I do carry spare batteries.

I already use multiple rear lights anyways so again I don't see a reason for a spare.

znomit

I keep one of these cateye sl-ld100s on the back of the helmet. Weighs nothing.

gmule

I feel your pain. I had one come off when I hit a bump turning a corner. It went down a storm drain. All I could do is watch it blink in the drain.

knucklesandwich

Took one off its mount on one bike a couple weeks ago and clipped it to the seatbag of my weekend ride. Sure enough, I jounced it off. I keep one clipped to my mess bag while commuting, and have a tiny clip on one for random times. Have a replacement to the good bike-mounted one in the mail, courtesy of Chainlove.

markf

One Cateye TL-1000 mounted on the bike, running in steady mode, and one Superflash on my seat bag, in blink mode.

Az B

I always run at least two lights ever since I got home one night and realized my light had failed and I didn't notice.

I figure with two lights, the odds of both being dark without me noticing is pretty slim. Plus, the lights are different and having two different blinking lights is slightly more noticeable, I think.

Az

TeamRoundBoys

I've got reflective stickers on my bike, (especially on rims, pedals) helmet and backpack. My pack has two loops on the back (Camelback Ethos) which sport blinkies.

Longfemur

Much more important to carry spares for headlight. Tail lights don't have as much value because if you have a good reflector, you pretty much have all the visibility you will need, unless some bozo is driving in the dark without lights on.

unixpro

Like many others here, I have two with both on. One is a PB attached to my trunk bag and the other is a bar light attached to the back of my helmet. FWIW, I also have 2 headlights -- one that's always on steady attached to the bike and another that's steady at night and blinking during the day mounted to my helmet.

pluc

My tail light is actually wired, hard to keep more than one for replacement. I have a Superflash that I used to use but I'm just so sick of battery lights, I don't use it anymore.

b_young

I have 2 on the bars of my rack, 1 on my helmet and a strobe on my bike bag. Also, two headlights. I have been told by a co-worker that he could see me from 2 miles back. I bought one for a backup and got the others for Christmas and just decided I was better off with all of them on.

hankbrandenburg

I run a PB Superflash on the back of my helmet, a Dinotte 140 on the rear rack, and keep a spare superflash in my bag.

KLW2

I lost one and then used a slice of a 27" tube like a rubber band wrapped around the light and clip..keeps the light on even over big bumps .....

MIKEnDC

Back in January I dumped it on some ice (slo-mo, slo-speed rear wheel said seeya fall). My Cateye stayed attached to my saddlebag, but the lens and batteries popped out in to the street to go promptly underwheel of the car following me--had the pleasure of hearing the crunch! Gathered up the parts and taped it back together at my desk and it worked fine.

Nowadays I run a B&M 4DToplight Permanent bolted to my rack and a PB amber blinky on my saddlebag. Both are firmly affixed, so I just carry spare batteries (I try to remember to top up the charge on them once a month or so). No worries.

JustBrowsing

I lost a rear blinky a few months ago on a ride (I remember hearing something weird behind me during my ride--I now assume it was my blinky falling off my bag, hitting my rack, and then bouncing off a spoke or two as it disappeared from my life). I ended up picking up a few cheapies at Performance last month (like 6 bucks each--don't want to spend too much more on something that can disappear with a bump). My trunk bag has a Superflash that's attached pretty securely, so I'm covered there. I only use my trunk bag when I'm commuting, so the other lights are attached to my weekend-ride seatbag.

Gonzlobo

No spare, no taillight currently installed. I'll get a TL-1000 when it starts getting darker.

jpdesjar

dont need lights on my ride
i just grab one when i know it will be dark, i have a few lying around

alpinist

One PB Superflash permanently mounted to the fender, another that attaches to the seat post, spare batts in the bags.