The World of Pokémon (A STH and Pokémon Crossover)

Age you have to be to get a Pokémon: 10+ (Depends on what your parents say, but no matter what, you can't be younger than 10)
All trainers start with 5 Pokéballs, not including the one that comes with their starters
Trainers get to keep all the Pokémon they catch until they die, but if they are put in the hospital or are dead, their Pokémon will be given to a responsible caretaker/or family member if they're dead/ until discharged