When did you use the foam elbow and knee pad inserts in UCP ACU's?

I used the elbow pad and knee pad inserts on my first deployment. As a .50 gunner on a HMMWV, MaxxPro, and Caiman, they saved me from a lot of bumps, bruises, and cuts.

Only on deployment, I didn't like the bulk of the knee and elbow pads, and the foam inserts were better than nothing.

Only the foam knee pad inserts since I hated the actual combat knee pads.