Well, it's not surprising that he trained right away, he is almost four and should be absolutely capable, not like when you train a toddler who just turned 2. If he's never used the toilet at daycare, he may not know what to do about it! He may not know if he should take himself, or ask to go, or even that he is supposed to. I would say that you and his daycare provider should talk to him together about using the bathroom at daycare, and the provider should remind him / take him to the bathroom every few hours til he's used to it. At about to turn four, I'd avoid the potty - that's meant for toddlers, he is old enough to stand and pee is in the real toilet. In a year, he'll be in kindy and there are not potties there. Both of my kids (one boy, one girl), trained right around their third birthdays using only the regular toilet.