Mike, I finally found this GREAT thread to help me with this technique. (Mine is a PC 7424.)
Can you or others give some guidance on how often to clean the pad?
I would imagine the first answer is it depends. I saw in another thread that, for swirl removal, you clean approx every two section passes. At first thought, this seemed a bit much to me, but maybe you are working with cars in worse shape or more material removal than I have done. Or, I am just making a common mistake

by not cleaning enough, perhaps in an effort to not use a whole bottle of product.
How about a few ranges such as for:
* Heavy cutting compounds
* Light cutting compounds
* Swirl removers
* Glazes
* Pre-Wax Cleaners
* All-In-Ones
* Sealants (I believe the answer is none on this one)
Thanks!