"If vitamin A comes from carotene then at least the body can make its own and it won't make more than it needs."

Carotene isn't vitamin A though. While the body can theoretically convert carotene to vitamin A, some may be deficient in the enzymes required to do this. Taking too much carotene or eating too many carrots will make your skin orange. While this is not dangerous, it looks very strange. Carotene is good as an antioxidant, however imo it is not a good thing to take for vitamin A. If you want to be conservative, you could limit vitamin A intake to 5,000-10,000 units a day, and also take some carotene.