I think the Munson plan sticky says how often, but here's what I'm doing.
Hatchlings to yearlings -- every 5-7 days, 5 days is probably better.
Yearlings to 2 year olds -- every 5-10 days.
After that it kind of depends on gender because I plan to breed, so the females need to eat more often, every 7-14 days, boys more like every 14 days so they don't get fat, and Pebbles every 18-21 days because s/he IS fat and is being slimmed down to a better weight (around 950 gms when I started the diet 6 months ago, has lost about 20 gms so far so we're making progress!).