I don't remember exactly but I'm pretty sure it was within a week.
It was over a clock change time and rather than doing 15 min increments which just does not work for him, I think I did 30min night 1, then another 30 min night 2, etc so by night 4 we were 2 hrs later than original BT. I think by the end of that week he'd shifted his morning WU (and the clocks had changed) and I brought BT 1 hr earlier, probably in increments to ensure the WU didn't fall back.
He was younger then of course, I think now I'd push faster because he's older.
...just hunted down my thread from last year. DS was about 2yrs 10 months. Everyone who supported me on the thread was worried about OT with pushing hard but it turned out brilliantly successful and he lost way less sleep overall.
Turns out I did 30 min increments for 3 consecutive nights. To save you reading the full thread this is where I summarize the shift:
Re: Any radical ideas for clock changeI started at BT before clock change, but I think it could have been faster if I'd pushed harder in the first couple days and there was a day I allowed a 30 min nap in the car which didn't help.
day 1 30min later
day 2 30 min later (total now 1hr - full clock change)
day 3 30 min later (total now 1.5hr so clock change plus 30 min)
day 4,5,6 same (ie 1.5hrs)
day 7 back 30 min (back to regular time, so full 1hr clock change but not plus anything)
(still waking a bit earlier than he should but has shifted almost the hour)
This gave us a night of 6.30pm to 6.15am. I know those times don't sound great but the point is the method not the times, his body clock was stuck at 5.15am. Pretty sure I did the same method shortly after, again pushing further than I wanted it to be to force another body clock shift.
This is the method I will be using this year at clock change but I will go faster because dawdling just didn't help, because he is older and will handle it, and because I am far more confident in making changes. My plan this year is to push 1.5 to 2hrs over 3 or 4 days and have the shift complete within 1 week, I'll prob go straight for a 1hr shift on night 1 then 30min to 1hr shift on night 2 and just get the job done.
FWIW anna says on that thread that she also pushed beyond the desired time, so pushing 1.5 to 2hrs to get a 1 hr shift.
Re: Any radical ideas for clock changeActually I'd probably go even later than the 'new' time. I did it a few times with Stan who was an awful and chronic EWer... it would work temporarily but he'd inevitably slip back to his preferred time of 5am - but you might have better luck than me! If bedtime before the clock change was 6.30, I'd do bedtime of 7 or even 7.30 (new time).
hth and good luck. Way I see it, it can't get much worse. When I posted asking for radical ideas I really felt I needed something radical, I'd done all the other stuff and he had continued to wake early for ever. Actually wish it'd done it much sooner despite him being young then.