The concept of readiness gets a bad reputation because it's sometimes used as an indefinite delay tactic. But the underlying science is solid. Here's what's actually true.
Bladder control has a real developmental timeline. The average child doesn't develop the ability to hold urine voluntarily — and to sense that they need to go before it's urgent — until somewhere between 18 months and 3 years. This isn't a cultural norm; it's anatomy. The neural pathways connecting the brain to the bladder and sphincter muscles mature on their own schedule.
Starting before readiness extends training, not shortens it. Several studies, including work by Dr. T. Berry Brazelton (who helped shift American training practices in the 1960s), found that children trained before they were ready took significantly longer to complete training than children who started later. The total "time to fully trained" was often the same or longer for early starters.
What readiness is NOT. Readiness doesn't mean the child is eager and asking to train. It doesn't mean they'll train themselves. It doesn't mean waiting indefinitely until some perfect moment. It means looking for specific physiological and behavioral signs, and starting once those are present.
If your child is showing several of these signs, they're ready — whether or not they're enthusiastically asking to start. You don't need to wait for enthusiasm. You do need these physical and developmental milestones to be mostly in place.
If your child is not showing these signs at 18–24 months, waiting another 2–3 months is usually more effective than pushing through. If they're over 3 and still not showing these signs, talk to your pediatrician — there may be something else going on worth investigating.