What is the closest you have 2 setups to eachother? I have one area that I have two that are 50 yards from eachother. Overlooking what is pretty much two totally different ways deer move through the area through 2 different funnels. Problem is it's a toss up (50/50) which one they'll use. I hunt one or the other based on the wind. Good thing (or bad thing) is I can't see what's going on at one while sitting in the other. Avoid driving me nuts. :p 0
I have 2 stands about 75 yards apart from each other. One is in an oak flat the other is hanging over a stream with mini food plot 30 yards away, stand selection depends on camera, deer sign and time of day. Only thing I can tell you is don't make it where you can see other stand and deer movement by that stand will drive you nuts sitting in other stand and lead to more movement in the stand which in turn will get you busted.
If you put a trail cam on both trails and record the weather and wind direction for each day the camera is out there I bet you can start to find some correlation between which trail they use to weather and wind direction. Once you learn which way they go depending on these factors you just need to compare your notes to the current weather on the day you want to hunt to know which stand to hunt. At least you can stack the odds better in your favor. But to answer your question I have very close stand locations as well.
I have some sets close together. It sucks sometimes seeing deer walk right by the other one, but at least you can make the switch next time out very easily. Also makes it easier to pattern the deer and another big reason for this is wind conditions. Sometimes you have a great little travel corridor that is used as a major deer highway and it pays to have a set on each side so you can hunt it in any wind. Thats how I see it, if the location calls for it then don't loose time thinking about it, just hang it and enjoy the benefits.
I have one spot that I bounce back & forth between two trees... they're about 8 yds apart. Face two different ways, great backcover between them, but I can't ideally cover then the whole area in one or the other. it all depends on wind and how I feel when I get there.
It's so thick here in S Arkansas that I'll usually have several that are relatively close to each other. I'm extremely lucky to have a clear shooting lane that goes to 50 yards. Anyway, with that being said, I'd agree that there isn't a problem with close stands/blinds as long as your use of one doesn't burn the other.
I have stands that are very close together mainly so that I can hunt different wind directions for the same trail/area.