i tend to stick to the same 1 or 2 baits during a year, but when the goings tough, you can either stick to your guns knowing that its gonna happen sooner or later, or ring the changes and see if you can "buy" a bite. but then i would always fish at least rods on the "going" bait.
if i was going to a water, i would only take 1 type of boilie...dont want to be worrying about when to try the others.
i made the same comment to stu ages ago at cottington, he had at least 300 different types of attractor pop-ups (well, nearly!) how do you decide which one to try? how long to leave it for? i now only carry 3, a fruity, a fishy and a spicey.