TL;DR -- This is a sanity check for me, regarding the question: Is it unreasonable for me to say, "No, you can't use the guitar that I keep in a case inside our shared rehearsal space." The problem is easily solved via a few different means (locking the case, or not leaving guitars at the space). Mostly just wanted to get the pulse from the community on this. Thanks for reading! Fuller story/OP: Help me out, community. I have been renting a room one night a week in a large rehearsal facility for several months now. Ours is one of the larger spaces in the building, thankfully, with plenty room to spare beyond a full drum kit, 5-6 guitar amps, keys, a small PA, guitar and bass cases, and a storage loft. I share this room with maybe 4 other tenants (individuals and bands), a couple of whom are friends of mine. I'm at least loosely acquainted with everyone. Most of the others were in the room before me, but I'm the oldest member of our little club by a decade or two (I'm in my 50s). Each room has good locks on the heavy-duty doors so it feels safe to leave our amps and instruments there. Several guitar cases generally live there full time, and I have been keeping 3 of mine there too. Currently there's one band in our room that provides a drum kit, with conditions for shared use -- this seems standard in my experience. Prior, it had been years since I frequented rehearsal spaces like this -- the stale cigarette smoke, the metal bands down the hall, waiting for the freight elevator... it's a familiar place for me, like going home again (though nowadays I could do without the smoke). I'm a former touring musician -- I've done this forever and I've been around the block. What seems less standard to me now is this: lately I've noticed that whenever I open one of my guitar cases, it's clear to me that my guitar has been used by someone else. This has happened at least 4-5 times now that I know of. I'm a creature of habit with my instruments, so there's no question about it. So... I know there are remedies to that (I'll probably start locking my cases, etc.). The reason I'm bringing it up is this: I've been in similar shared studio situations all through my professional life (except for the last 20 years of parenting), and there has never been a chronic situation in which I felt like I had to raise this issue with my studio mates. I've personally never felt entitled enough to just blithely pull out their instruments when they weren't there, and either they were equally respectful of mine or they were clever enough to not be so obvious about it. Back then, the unspoken (or spoken) rule was that there would be hell to pay if people played other people's instruments without asking. There's another aspect of this: I think I know who's doing it, because they finally asked me (via IM) if they could -- after I'd been aware of the problem for several weeks. The guy is not one of my friends. So, asking is nice... but then that puts me on the spot. I want to keep the vibe cool and all, and saying "NO" out of hand seems "un-mellow". But to be completely honest, I am not cool with it, and it's bizarre to me that anyone would be. Furthermore... where's your guitar, dude???? And: Would you be ok with my just deciding to play your guitar? Being cool about stuff like this is fine I guess, but I feel like there are plenty of good reasons not to let people play your instrument. This post is long enough already -- maybe they'll come out in the comments. But I'm curious about your experience with this. Am I the uptight one? EDIT: I should add, the guitars I leave there are not my most precious, valuable instruments -- those stay home, I'm not THAT crazy. These are not so precious that I'd be heartbroken if they were damaged or lost, but they're good enough that I enjoy playing them and, yeah, I'm not comfortable sharing them at all. It does seem to be a surprise to some that I'd leave ANY guitars there -- truthfully, this is how it was always done back in the day if you knew your studio mates and your room was secure. And as I said, others do this in my room now -- I just can't imagine they'd be as ok with my using theirs as this guy seems to be with his using mine. So maybe I AM the uptight one, if I'm willing to leave a guitar in the space but not share it. Weird!