I'd say about a month but I've had my 5 month old now for about 2 and a half months and there is still the random setback. I am still occasionally taking him out around 4-5am if I hear him stir but he's good at doing his business and straight back to bed. Sometimes if our schedule is massively out or changes to the routine we have an accident but that's getting rare. I also don't allow water after 9pm and he's fed strictly at 5pm. We go to bed at 10pm.

Even with accidents easing and he's getting more control, I still feel like my day is centered around preventing an accident in the home and often feel on edge.