I have fitted DaveW's fantastic lower spring gaiters on the front of my Plus 4. After a track day and a reasonably long jaunt I thought I owed the car a little TLC, and did a spanner check/underseal top-up/front suspension re-grease. It was probably 500 miles since last greasing. I was amazed at how much grease there was on the inside of the gaiters - perhaps a depth of 5mm at the thickest point.
Just shows how much was being lost to the environment, and probably onto the front disks, before the gaiters. And how important it is to keep the greasing routine up!