Inner brake pad wearing faster than outer pad

[mikepier]

I went to check my front pads the other day and saw that the inner pad wore a little bit more than the outer one. This was on both wheels. Is this normal and what causes this?
I swapped the inner and outer pads so they could wear more evenly.

 

[Silver X]

You need to make sure the caliper is free to move on the guide pins. If there is corrosion or junk built up on the pins, the caliper will hang up. You will need to clean or replace the pins. Grease the pins before installing them.

Also make sure the pads are able to slide on the little metal clips. If there are grooves worn in them or brake dust clumped up, the pads will hang up and contact the rotor longer than they should. Clean or replace the metal clips. Add a light layer of grease on the clips, but only to the surfaces that the pad tabs ride on.

The clips are shown at the top in this pic: