i've never really regretted any gear i've bought, or any that i've gotten rid of
there was a guitar i bought once that i probably paid a bit too much for...but i ended up trading it to a pawn shop for a better guitar later on, so i pretty much broke even there
the only stuff i've ever gotten rid of was because it was broken, or i had just totally outgrown it. the only gear i'll buy now is stuff that i plan on keeping for a loooooooong time.