Recently we have a new developer in our team. We are getting him up to speed and he is picking it all up quite fast, but a new developer means new (foreign) coding styles and ways to solve things.

It feels kinda petty to start whining about coding styles at the first three classes he codes, but how forgiving are you guys when dealing with new developers? Do you let them muddle on, and point it out later? Or do you wield the scepter of intolerance immediately?

When do you draw the line, or if not, why not?

P.S. New guy, if you read this: you are doing great, keep up the good work ;)

Edit:

I've accepted the most up-voted answer, as most answers share the same message: Be nice, but tell them asap! Thanks all for the nice answers! Really appreciated it!