Inspired by an idea from Kon93, I decided to do a poll.
1) Develop all his powers instantly as soon as he's under a yellow sun. (pre-Crisis, Ruby Spears)
2) Some powers instantly and others later. (Smallville, MOS, Donner movies)
3) No powers until puberty. (post-Crisis, Lois & Clark, TAS, SO)
4) Natural super strength enhanced by a yellow sun. (New 52, Golden Age)
5) Keeps getting more powerful as he gets older. (Kingdom Come, Generations)
6) Gets weaker as he gets older. (Superman Beyond?)
7) Other.
And, yes, you can pick more than one. Or add your own if you think there's something I forgot.