I've always heard that taking off the diaper or being dry through the night are NOT signs. The signs I've heard are:
Fascinated when others use the potty.
Able to go 2 hours (or more) between wet diapers. This may be over a nap or overnight but that's not necessary. 2 hours or more while awake means they are starting to hold onto their pee and can control the bladder.
Willing to sit on the potty - either the big one or a little one. You won't get anywhere if you have to force them to sit on the potty.
Is not in a negative phase - "NO" is not the first, automatic response to any question you ask.
There are no big changes in the household planned for the next 2 to 3 months - no vacations, no guests, no new pets or babies, no new schools.
You have the time and patience to deal with the mess and stress.
But you can start anytime if you keep it low key and don't force.
at 12:20 PM on Apr. 28, 2009