I usually go up about 20' or so, but like others said, depends on the topography and how high I feel I'm still comfortable. Also, like some said, make sure you have a safety harness on the moment your feet leave the ground until the moment they touch it again. Even falling a few feet, at the wrong angle or with big sticks pointing up, can be catastrophic. Quicky funny story.. I went out on public property around where I live (Maryland guys will know.. Liberty Reserviour) and there is a very wide, very heavily used main trail (hunters, fisherman, hikers, joggers, horseback riders, ect) that goes around the water. I was hiking in for my afternoon hunt and ran into a guy who was maybe 5' off the main trail and couldn't have been more than 6' up a tree. If that wasn't funny enough.. The guy even used a hand truck to haul in his gear and had that sitting at the base of the tree! I even stopped and told him that he was way to close to the trail and there is a spot about 100 yards away that sits on top of a large, steep him with a deer path below.. he would be better off there. He told me that he was good where he was at. All I could do was say good luck, walk away and try not to bust out laughing.
I hunt from ladder stand most all the time. 12 to 15 ft. I rarely get spotted by a deer. The key is having cover behind you to break up your form. Sometimes you must get on up the tree depending on the area. I will say that higher will be better for scent but as long as you can keep the wind in your favorer then you are good.
sota for hanging a tree bigger than your waist like a oak tree isnt for a first timier like him. when it comes to hanging high. dont go there yet. id start hanging low like 8 to 10 feet high for beginers. once you get used to hanging stands. then cautiously hang higher only if you feel confortable.
I tend to go pretty high 20-25' but it depends on the tree with back cover from branches, etc. I like being up that high as by me the age of the forest you are above a lot of the ground cover/smaller trees so you can see through the woods and have some nice shooting lanes without too much cutting. I also like to be that high as I believe it helps some to keep from getting winded for in certain stand locations. I could be imagining that though. I think back cover and staying still are more important that height.
To me, it is really a call of the lay of the land and your comfort zone. I typically go 20' or so. I am not a fan of heights, so 20' is about my comfort zone. I try and get in where I have back drop of branches/leaves or whatever behind me. Anything to break up my outline. No matter if your are going 10' or 30'.. make sure you have your safety vest/harness on and teathered to the tree.