When they were babies, the main cost was childcare. Primary school, there was still breakfast and holiday clubs, school uniform etc, but infants was okay...
Then juniors, and the hobbies started. Obviously encouraged by me, as they get a huge amount from them, but I think I'm spending around £5k a year at the moment.
Secondary school, still paying for hobbies, nothing on childcare, but the food! And the clothes! And the shoes!! Eldest has grown a foot in a year, and gone up three shoe sizes. So that's 3x school shoes, 3x school trainers, 3x home trainers, 3x tennis trainers, rugby foots, football boots, Converse, walking boots. And he is happy to wear pretty much anything, and doesn't actually care if his shoes are too small.
Then the school trips which say "don't buy anything especially, but they need.......10 t shirts, 5 pairs trousers (not jeans), 5 fleeces, waterproofs. Oh, and the following shoes: dry trainers, wet trainers, indoor trainers, trainers for the disco, flip flops, walking boots, wellies......