Every situation is different... The higher you get, the farther away from the deer trail you should be for proper angle. But even if your hunting low, letting deer get to close often leads to getting busted. They are very sensitive to movements and noise within about 10 yards. I personally like to shoot them from about 18 feet at 16 to 20 yards...

As far as how often you should check your trail cams? You can get away with once a week or whatever as long as you have them placed away from your hunting areas... I rarely ever put a trail cam next to my hunting spot. Only on perfect conditions like during a rain, or on a day I am hunting there.