It depends on a few factors.
Is it a hatchling?
Hatchling feedling, any issues and how you over come them
Are you breeding this coming year?
Feeding & breeding Female
Are you trying to gain weight fast?
Grow ‘em Bigger, Faster…Breed sooner!
…
Personally, I’m not after bulking up any time soon so I feed every 10 days no matter the size. If someone doesn’t eat someone gets 2.