Q: Do I have to adjust the wall clip each time I use it?

A: No. Once you fit your clip to a controller properly it holds it's shape. I suppose It's possible that over time it may loosen up. If it does feel loose, just give it a squeeze to tighten the grip and pop the controller back in.

We've been using Wall Clips since October 2008, had (at one time) controllers sitting in them undisturbed for 3 months straight, and never had one fall out.

One thing to note: When removing the controller from the clip, do not twist to remove it. Twisting will tend to bend the legs out of position. Just pull straight out as demonstrated in the using guide. If you have to twist to remove your controller, the grip is set too tight. Stretch the bumpers apart so you can just pull it straight out