I was reading some discussions on condensation and am inclined to add my experience with putting a new fuel tank /sending unit in my 1996 Chevy truck. After installing the tank and adding 5 gallons of fresh fuel I pulled my truck out of a heated garage (app. 50-55 degrees) and (app.20 degrees outside temp). I plowed snow with it and parked it for the evening. The next day it would not start. After try either to no avail I pushed it back in the garage and added a red bottle of heat (isopropyl alcohol). Several hours later it started right up. I must assume that it was due to condensation as I have not had problems with water in the fuel prior to this.
I can see where keeping the fuel tank full may help, but who keeps their fuel tank full all of the time. My thoughts are that someone who parks their vehicle in a heated garage subjects themselves to this problem on a daily basis, ergo is it even practical to use a heated garage?