I like to check them weekly when I can.Some times things go haywire and it is just a good idea to make sure things are working OK.I have had weeds grow up in front of them,and waving in the wind,they caused a false trigger every minute till I was out of memory.I have also had limbs move or get knocked in front of the camera,bears move them etc.
It is just a good idea to not wait a tremendous long time before checking them.Visit them during the middle of the day when animals are laying up and don't go near bedding areas to do it.I also sometimes go when the weather conditions are such that chances are slim that I will bump into game.I also "still hunt" into my cameras,even when not really hunting.It's good practice and it makes your prescence less obvious.