I watch the "dust" that is on the pads. When I can't really see it as I spray/dip them in water, they have dropped down ( or up depending on how you look at it ) and I change the number with a Sharpie.

Once they have gone from the "new grit" them I cut them up and use them to smooth out a thumb hole or my wife takes them when she repaints a vehicle.

They also make nice cleaning pads on anything that might not scratch.
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az guy aka: R & L Bowlers Pro
rlbowlerspro@cox.net
www.rlbowlerspro.com

ttt. is there not an answer out there for this?
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Go Buckeyes!!!

Heres what I seem to get out of mine.

Dry sand - About 3-5 uses before they dont cut down to that grit any more

Wet Sand - About 10-15 uses, getting more out of the finer grit before they dont cut that grit any more

Say with the 500 pad, after the uses I get, I just mark them the next grit up untill there trash, which for 500 is about 15-20 dry sanding and 40-50 wet sanding. And it goes on from there.
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"Nothing Hits Like A Hammer"