Depends a bit on growth rate, but generall mine (a 5 month panther) is shedding every other week.
Shedding seems to be very quick, and is usually over in less than a day... normally the only clue I have that a shed has occured is a few bits of old skin on the floor. Last shed the I could tell it was about to happen as he had a small patch of loose skin on his elbow, when I got back later in the day he was all shiney and new!
The colours do develop through shedding, and felix is now generally green, and has lost his baby colours