I find it really awkward when they start out growing toys but aren't teenagers/adults. This year the only one I had plenty of ideas for was DS3 who is 8. He still really loves his toys, so there were loads of ideas there, he's also home educated so there was tons of educational stuff that looked fun, and he had loads of ideas of his own so I've finished for him and there's still a ridiculous number of things that are possible birthday ideas. The older two haven't played with toys for years and DS4 is starting to slowly out grow them, he's 5 next week!
I have managed to find a decent amount of things for each of them though and only need to get a few little bits now.