The kittens need to be weighed and examined every day. When the kittens need to be weaned, you ll have to make sure they get adjusted to their new diet. You also must spend hours of time with the kittens to socialize them well. Especially when you have kittens, you must take extra care that the cats are in good health and they have no parasites. Most breeders take their cats to shows where they will be evaluated by a judge who can point out their possible weaknesess.
Cat shows take time, and they also cost money.