I have a couple of guitars and I just made some mods to my Gibson SG which is by far my favorite. As of now, I just keep all of my guitars on stands throughout the day. None really just stay there either I tend to play them all as they serve different purposes. Since I invest money into these guitars and I want them to last me as long as possible, I've been wondering if just leaving them on their stands is okay? My room is pretty small, and I hardly let any sunlight in because I'm not usually home during the day. I don't want dust to get on my guitars or strings to dust quickly. I have a couple of gig bags that I can store them it, but would that be better? Should I invest in some hard cases instead? Also, I live in SoCal so if there are any other guitarists from SoCal here that could let me know about how they store their guitar in our weather it would be great. Humidity is a thing I lack knowledge of and I don't really know if it's too humid or not to keep them in my room
I'm in LA. I keep my guitars in their cases.

I've found that strings rust a LOT faster if I leave my guitars out (even lying on a bed).
I have other issues with leaving the guitars out (besides dust, salt air, etc.) that include three athletic cats, earthquakes and a spouse who...uh...cleans with abandon. I've also got friends who like to pick up whatever's loose and pretend they're playing, and particularly so during parties when alcohol is flowing.

You'd be amazed at how much dust can be in the air in SoCal; I've got keyboards and speakers in the same small room, and I've had to put keyboard covers on those just to keep them from getting nasty with it. During a Santa Ana wind there's a ton of dust carried in from the desert, and when you've got onshore breezes, you'll be very surprised how far salt and moisture is carried.
dspellman That's the one issue I found. I recently restrung my SG and within days I noticed rust on the strings. Do you think just gig bags would suffice? I only have one hard case and that one's for my sg. I would love to get more for the rest of my guitars but good hard cases can be pretty pricey.
Personally speaking, I have my guitar, bass and violin in their cases and I store them flat on top of my bookcases. Seems as a good a place as any to me.

Don't store instruments near heat sources or laying on the floor.
I keep mine in their cases, that way it will help prevent dust build up and unwanted accidents. But up until a few months ago I kept my electric on a stand but it had an accident and now has a gash on its face. So my advice would be to keep them in a case.