-makes sense for TTs so one can stay in position and still hydrate, particularly when the TT is part of a stage race and recovering effectively from the TT effort is important. everything TT is fred so that just adds to the aura.
-RRs, kind of makes sense too since you will likely need more than 2 bottles and maybe it would keep you cooler (?)
-Crits, I cant see why it would be necessary. The crits you'll be doing are <60 mins and many are 20 miles (more like 40 to 45 minutes). I normally only carry 1 bottle because the races are often too ballistic to get through more than that, but have carried 2 bottles on occaission. Just reach down and get a drink from your bottle.