I change the micro filter every water change (3 to 4 months), and clean and swap the pleated filter at that time. I don't clean the pleated filter between changes, as it doesn't get that dirty. I swap between 2 filters, and I hope to get at least two years out of them.
Ten years is longer than I'd expect to get, but then again, I only have a year on my tub so far.
Brewman