dd1 turned 4 last week. She has been dry in the day for almost 2 years. Up until last Sunday, she was wearing pull ups at night. Most mornings they were soaked through. About once every couple of months they would be dry. For a week before her b'day her pull ups were dry so she decided (and we agreed) she should try without. The first 4 nights - great, totally dry. The last 2 nights she has called us around 5am due to being soaked.
My gut instinct is to forge ahead at least for another week or so. We do all the practical things - last big drink at 5pm, wee before bed etc. We have a waterproof sheet and spare bedding and pjs to hand to minimise disruption.
Before anyone mutters that I am being a bit lazy (!) I feel I should add that I am only getting sleep in 2-3 hours blocks anyway as dd2 is 4 mths old and exclusive b/f, so I could really do without getting up at 5am as well! Dh btw does his share but dd1 gets quite loud in the night and disturbs me anyway.