Liz -- It depends on how big it is and how healthy it is. I start cutting back at about 3inches to every other day. Some may differ, but that is what I do.
Flyjawn, what matters is the total amount of pellets the turtle gets. If you're supposed to give a certain amount every other day, but want to divide it in half and give it every day, that's fine. Lots of us with adult turtles do that - we give a half a headfull every day instead of a whole headfull every other day because it makes our turtles happy.
Some people with little turtles that are supposed to get a headfull of pellets every day divide the headfull into three or four tiny little feedings and give them throughout the day because they love to see their turtles happy. Just be careful not to get carried away and give too much overall.