.... until they're about 10, involving them from primary school age where possible, and to encourage and remind them to do so after that until they become self-sufficient in their teens (hopefully).
It's no wonder there are so many people (ok, almost exclusively men) out there who are so rubbish at remembering, organising and getting presents/cards if the behaviour is never modelled and taught by parents in their childhood, as exemplified by the 'but he's not their mother' comments on all the Mothers' Day threads.