Ive had a retained clutch as early as 5 weeks and as long as several months apart. I believe it has to do a lot with how she is being fed and the temps. Once they become breeding age I like to keep a laying container in the cage at all times, just in case
The amount of food will play a huge role in egg production. from the number of eggs to the frequency of clutches. the more food, the more eggs and quicker turn around. keep in mind, this will also mean higher stress on your cham.