My spa gets fairly regular use. Every day or every other day. I have ozone with a 50 square foot filter and filter cysle set at 2 hours twice a day. I spray my filter off weekly, but it is rarely very dirty. When I soak it in cascade, I do find some oil and debris wash come out, but not a ton. And my water is clear as can be (with only a couple random exceptions).
My point, I think filtration is important, but smart tubing is even more important. By that I mean the cleaner you are going into the the hot tub (and while you are in it), the less need you have for filtration.