As a general rule this is what I do, but I adjust it for individual animals as needed:
-fresh hatch for ~3 meals every 3 days a hopper mouse (or pinky rat)
-till 200g- every 5 days a small mouse (or rat fuzzy)
-till 350g- every 7 days a rat pup (or freshly weaned mouse) *this is when I personally swap to rats*
-till 500g- every 7 days a weaned rat (or fully grown mouse)
After that, it depends on the sex, and whether or not they are breeding. 14 days might be a little premature, you might be better with 10 at this stage, but you will just have to watch how he does. If he starts to thin out too much, you can go to 10. 14 is a good maintenance diet once they have reached mostly full size, which for a male is about 1000-1200g. Females are a bit trickier, but for pet-only, you can do roughly the same thing but till 2000-2500g.