Mine are 13 and 18 now, but I still buy lots for each. Each stocking will have a book, loads of chocs, a game, pj's, smellies, socks, novelty items etc like a personalised mug, mini puzzles.
Under the tree, an outfit each, more pjs's, dressing gown and slippers, calendar, more books, new duvet sets, about £100 each in vouchers, normally a vans type bag each, and a 'big' present each normally about £200 each for that, new headphones and computer games and lots of little bits
I grew up very poor though, never had a Christmas stocking in my life until I met dp, and he puts one on my bed every Christmas eve. The thrill I get from that bad boy every Christmas morning (the stocking...NOT dp btw
is amazing). I appreciate spending a fair few hundred on each child may be excessive. But, other than birthdays, I don't get them anything really. And I love that they always appreciate it.
That said, I've had some frugal Christmases as a kid, but DM always made the best of it on a tiny budget and I have some great memories. It's not really about what you can afford or spend on Dc's that matters anyway. A child can have the same joyous reaction to a gift from the pound shop or a gift that costs 100 quid.