We all have a sweet spot in terms of bike size, that perfect fit where the seat tube length and the top tube length are just right. My question is..... do a lot of you stick to that size and only consider "perfect" fit bikes for purchase, or do you have bikes that vary a little in size. And if your bikes vary a little in size (particularly in the seat tube length) do you feel it is easier to deal with a bike that is a size smaller than your perfect size or a size larger than your perfect size? And what are the consequences with regard to comfort, aches and pains after the ride, safety, etc?