I bring water with me and sip every mile whether I'm thirsty or not, plus gel every 40-50 minutes.  I don't think that I really "need" it at the distance of my long runs (up to 15 so far), and I have run 14 without anything, but my plan recommends it, plus in the humidity where I am running now, I sweat a ton.  I find I recover better after my run if I stay hydrated during.

I usually use the water fountains. But if it's some type of run where I can't stop, I'll take a handheld with Gatorade. Actually now I'm testing my new Simple Hydration bottle.

Generally water on a long run (> ~90 mins)

 

Hmm, the center of the back huh?  That is interesting.  How does it feel to carry when full and what type of paces have you run with it?

So far easy, and fast uphill (wore for hill repeat session). It was a bit bouncy at first, but I totally forgot about it after the first couple of swigs. I'll be in a better position to give a more thorough assessment after this coming thursday's tempo. So far, I am optimistic and I don't think I'll be using a handheld anytime soon. Since it rests on your back/ass, it does warm up so I'll try it with ice next time. Hopefully I don't literally freeze my ass off.

Depends on the LR and the weather.

Up to about 15-16, I may not drink anything if it's cool out.

Further than that, I will stop at least once for hydration, more if it's hot.

Marathons, I've learned to get sports drink/gel calories at *every* station and additionally grab water as desired.

Just finished 18.6 miles in 2:30:04 this evening.  Temps were in the low 80's when I started with very little cloud cover although the dew point was 65 so not too bad.  I tossed some small hills into the mix for a total elevation change of roughly 350 feet climbing and 350 descending.  I also did 12 x 1 minute pick ups at HM-10K pace with 1 minute recoveries after Mile 15.  That was the workout.

I stashed two 24 ounce bottles that were frozen solid.  I drank what was available (maybe 6 ounces) out of one of the bottles around Mile 4.  I got a bit dehydrated and started to overheat a little around Mile 11 but that was also when I got to the 2nd bottle.  I drained what was available in that bottle (maybe 12-16 ounces).  That was the last thing I drank before I finished.  So, I had maybe 18-22 ounces that got me through the run.

I did a 15 mile run last week and the temperature was lower but the humidity was awful.  I was soaked by Mile 3.  Didn't drink anything until the guy I was running with and I hit a water fountain at Mile 11.  I drank a bunch there.  Did the last 3 miles at marathon effort.

As a general rule, I think people take way the hell more shit with them than they need.