Frequent diving and bottom cleaning is already a part of our routine. That includes checking and changing anodes and checking running gear. Also, if one wants to see themselves, you can see pretty well with a gopro or similar camera.
There are a lot of factors, including location, use of boat, and type of paint used.
We clean very frequently due to our local waters (monthly if sitting in Fort Lauderdale. If cruising, far less frequently) and the desire to not have to scrape, but just gently clean and to maximize performance. I consider the need to scrape as a sign we didn't clean frequently enough. We haul once a year just to look closer at everything, however, and generally refresh the prop speed at that time (props and running gear). We anticipated bottom painting every two years but it's actually run three years and even then not really been to the point of "visible need" but just not wanting to press our luck. When we pulled to paint and the yard looked at the boat, their reaction was "has it really been three years?" We use only hard paint, no ablative.
The standard in our area for lightly used boats is monthly bottom cleaning, annual prop speed, every two years on bottom paint.