slominer,
At what age is it kinda late to wait to, to start toilet training a toddler?
I think between 2 and 3 years old is most common, though a few kids might show readiness before 2, and a few may not be fully ready until 4. Beyond that, one should probably schedule a visit to the doctor to rule out any underlying problems. Nighttime bed-wetting beyond age 4 is more common than many parents (and kids) think, and doesn’t necessarily mean there’s a problem.