I posted this on the 0-3 month board, too. Would you reuse a bottle during the day before you sterilized it? Obviously, rinsing it out...but not washing it at all. (BF, obviously)
I don't sterilize bottles, but I can't think of a situation where I wouldn't be able to do a quick wash with soap and water. I think I would only reuse it without washing if I had to.
Re: Reusing bottles
We've done it but I always followed the 5 hour rule for milk at room temp (if that makes sense) and only reused it once before washing.