I personally recommend no more intervals for cleaning during the season, just once in the spring. Up until just a few weeks ago I had to haul every 4-6 weeks to clean the hull bottom of all the sea life that accumulates then re-wax the whole thing. It was always a big ugly dirty $hitty job on my back moving on a creeper. After six miserable seasons of that ugly job I finally epoxy barrier coated and then anti-fouled with interlux CSC ablative. I now look forward to no more of that god awful BS of hauling and cleaning 3-4 times a year. It took me six years of hard labour to learn the hard way and paint the dam thing. Don't be as stupid as me and take that long, learn from others and paint the first season out.
Of course, the frequency varies with bottom paint, the location where you keep your boat, and your fastidiousness. Last season (seven months with Micron CSC) my crew and I scrubbed the bottom once, I hauled and cleaned the bottom once, and had a diver clean the bottom twice. Three of the four cleanings removed hard fouling. I've raced on boats with Baltoplate where the skipper clean the bottom weekly. I'm convinced that the location is not only a macro question but also depends upon micro conditions; boats in well-flushed harbors fould quicker than those in basins where poor circulation allow astew of toxinsto accumulate.