Its all about the hunting environment, wind, and location of stand. I personally like to go at least 30 feet if the canopy from saplings is not blocking my view of my surroundings on the ground. It helps my scent (better than 15') and it gives me the opportunity to move a little bit more while hunting a full day.

Forunately I have a ridge overlooking a creek bed with tall beech trees, poplars, and birches. I put this stand up with 5 sets of 4' ladder steps, and facing east so when the sun comes up my silhouette doesnt give me away. Between the 20' ladder steps and the 20 foot ridge below, its pretty much 40 ft to the trail with at least a 60 degree slope to the bottom that they are using to come up the ridge (10 yrds from tree) to my clover plots from the creek bed. It also gives me extremely long views during the fall when the leaves fall for my muzzleloader. I have taken deer on the other side of creek at 200 yrds since my view was unobstructed.

The answer to your question, however is how safe you feel, and ALWAYS strap yourself in while up there so there are no doubts of your safety. Thermals in the hotter days keeps the scent higher but make sure you have trees to cover you from behind so you dont stick out!...did I mention KEEP your strap on and NEVER carry your gear while climbing? Always keep a haul line, or if you are using climber, pack it in your gear!