When is it worthwhile teaching "please" and "thank you"?

[MrsJamin]

Have a friend who is insisting that her (just turned) 1 year old DC signs please and thank you in the appropriate way - i.e. won't receive anything/food until he signs please. Surely it's too early for insisting on manners? Am I being lazy by not being bothered about it for ages (I have a 9 MO)? It just seems a bit odd to me. When did you teach your DC to 'say' please or thank you?

I would say that it was automatic. I wouldn't sign, just always say it myself and expect them to as soon as they could talk.

I always remind them to say please and thank, Ds1 2.9 usually says 'may I have' which I allow instead of please as it is polite.
However I think witholding stuff at a year is somewhat OTT.

Start 'em early, I say.

Worth it from the start. 'Tank oo' was dd's first recognisable word. She was copying what she heard - I wasn't prompting her to say it.

Mind you, I still sometimes need to remind her at nearly 10.