Since you have to set up a cam close to your subject it's easy to tip off deer if you don't use scent control and move the cams at least 7 foot off the ground also get yourself some black flash cams you won't push as many out as you might think or have been told. I spray my cams down and I give them a few weeks before I check them. Just like in bowhunting every time in to your stand you tip off deer to what you are doing,same for cams. Cams over bait or mineral licks seem to be more resistant to deer caring what's going on but deer will not tolerate a lot of activity on trails and will quickly adapt and move around cams.
