Everything is replaceable. If not with the exact same thing then with something that will do the job.
Emotionally, I can't do without whatever guitar I just purchased and where I am still in the honeymoon phase.
I NEED equipment like cables, pedals, and amps, but there's something about guitars that I just LOVE. The way it looks, how
it feels in my hands, etc.
Probably the most indispensable things that I have that would be a bit harder to replace are my Rivera SuperChamp and
my '72 black-faced SR with CTS Alnicos. But there's no question that I could replace them with a decent Fenderish amp product.
I've been fortunate enough to have been able to afford some pretty high end gear over the years, well high end for me, and I've determined that the one piece I can't live without is my 2011 Baja Tele. I simply love everything about it.
For me, right now, it’s kind of a toss-up, and at the forefront of my mind because I want to do a gear purge.
Two things come to mind: my early 90s Peavey TKO 1 x 15 bass amp is a great utility piece of gear. It isn’t really powerful enough for bass use with my band, but it’s flexible and solid-sounding for practice or recording at home. It also works really well with my guitar for a bright, snarly, kind of compressed crunch that cleans up well with the volume knob. And it can be EQed to sound decent for clean lap steel too.
The other piece is an old Zoom B2, which I bought used to use as a preamp to drive a power amp and bass cab. I gradually tweaked a user patch slot to a bass sound I really like, and then discovered about four guitar sounds in it I really liked, and then discovered with a little more tweaking one of those guitar sounds also sounded good with lap steel...
Some kind of Strat and some kind of AC15 if I'm playing electric -- these days a Music Man Cutlass and a Bad Cat Cub 15. National Resophonic Style 1 Tricone is the indispensable acoustic. Current favorite one-pedal-to-rule-them-all is the Nocturne Brain El Pescadoro.
I’ve got a Martin slot head dreadnought that I’m fond of. The neck joins the body at the 12th feet so it’s nice and warm sounding. And it’s serial #7 so that makes it lucky imo. And I need all that I can get!
Easy! My Martin OOO acoustic. I could be very happy having that as my only guitar (but have over 30, over half are acoustics).
Also have an acoustic 12 string, an acoustic tenor, an F-5 mandolin, a five string banjo, a fiddle, a mountain dulcimer, a bass, a keyboard and three ukes. A lot of different tunings (and fingerings) among all those.