Too often I have noticed that tanning beds irritate our skin. They can make us splotchy, or give us red, irritated patches of skin. The camera picks up pretty easily on differences in skin tone, so I always advise not to jump in the tanning bed.
However, if tanning is something you do on the regular all the time, I would just suggest not going at least a week before your session.
Here is where I personally stand pretty firmly in my opinion. Spray tans are not necessary for your session. Believe me, I know you want to look like a goddess for your session. However, a spray tan just isn’t the way to go. Too often spray tans are patchy or uneven. As subtle as it may be to our eyes, the camera picks up on that uneven skin tone so well. You’ll see darker, splotchy areas around your wrists, fingers, elbows, knees, and feet. This is almost impossible to edit out and smooth over, so that patchiness will end up being visible in your photos. You could also appear orange, and no one wants to look like an oompa loompa!