If your going to reuse Cometics, should you resurface your aluminum heads or is that not necessary?

Anyone had issue trying to reuse Cometics?

I don't feel any grooves or indention in the heads caused from the Cometics so I guess it just flatens out the raised sealing rings on the Cometics (I was mistakingly thinking it would leave grooves in the heads like when you O-ring the block).

I've got both of my motors apart (Abbey's and mine), her Cometics are new from last year. Mine are about 3 years old.

Not sure I really want to take a chance but considering it so I wanted to get some opinions from you guys.