Don't buy a guitar or amp you won't use on a gig!"..ya and/or the studioThis is just me, but I ( now, didn't used to be like this) prefer to have an assortment of cool individual ( and stock-spec) models ( one Strat, one Tele, one LP, Etc.,)
than any duplicates of a certain model.
This mind set came from my needing to sell a bunch of guitars ( over years) that just weren't getting played, and I needed the $$.
But at the same time, in moderation, I get a new ( or used) once in a while, always something different.
* also, I know not everyone plays gigs, but my other rule is
" Don't buy a guitar or amp you won't use on a gig!"