I don't have specific guidelines, but I don't initiate, I wait until the parents have started at home too. Last summer, dcb was trained when he came back after my 2 week vacation. Yah.

I tell parents I don't do pull-ups as they don't hold nearly as much and if there is any #2 then the #1 overflows and you have the same mess. Undies all the way.

I have had parents want to start too early, before the child is 2 and is not even close to being ready. This is always a disaster and I think it actually has lead to the child taking longer to train in the long run.

The biggest issue is always the spare clothes. Some parents will bring 2 spare pants and 2 underwear and 4 extra shirts. Huh? How does that make sense? And bringing clean clothes after dirty ones have gone home. A constant headache. I have some spare clothes here for this reason. On a couple of occasions, I have sent boys home in bright pink pants with my daycare name written up the legs in marker. No forgetting whose they are...those come back. lol

Nap time is different, I don't expect them to be able to sleep through in underwear at the beginning. Diapers are ok while they are getting used to the whole process.