No more than 2 times a year typically. If the female seems to be doing poorly I concentrate on keeping her healthy and probably wont ever breed her again. I usually gauge this by how easily she lays and how quickly she goes receptive again after laying. if she is feeding and drinking well and seems in really good overall health I will put her with the male again later in the year to ensure strong clutches. Retained clutches will typically have lower hatch rates than the first but not usually by much. for say 30 eggs for 3 clutches you should get 100% hatch rate for the first clutch, possibly lose 2 for the 2nd clutch and maybe lose 3 or 4 eggs in the 3rd clutch. If I breed her again to the same male when she goes receptive, I have 100% hatch rates every time. Hope this helps.