Last chapter of Jenni and Winkler is various strategies birds use to fit the moult into the bird's annual cycle.
If they have any choice in the matter, a bird has to decide between the need to moult because of declining feather quality or change of appearance required, set against the need to perform other tasks with a tolerable reduction in plumage performance, that is, without moulting. For many species, the best compromise is after breeding, when offspring are developing, which usually coincides with the best, or at least benign, environmental conditions of the year for that species (comfortable temperature, plenty of food etc.). Most moult once a year, but some up to 3 times a year, and some so partially that they are effectively moulting all year round, a feather or three at a time. Much depends on whether or not they need to fly or be waterproof, and whether they migrate or not.
There are 6 principal patterns to juvenile moults. Most have a partial post-juvenile moult and get into the adult pattern for their species in the 2nd year; in some large species with incomplete serial moult, juvenile remiges may be retained until they are 5 or 6 years old!
With that chapter the book ends and I'll bring this summary to a close.