I get the having things for best. We go out with DS regularly. He wears his nice clothes then. Eg. cinema, bowling, meals, shopping, trips to relatives etc.
Other older clothes are for general wear, ie. own clothes day at school, dog walking, bike rides, playing in the park etc.
I'd definitely stop the pocket money. Or another suitable punishment of your choosing.
I'd give the washing machine a go with the trainers, buy some new laces, or bleach them if they are white. I've been surprised in the past at how I've managed to revive them
I had to buy DS new shoes yesterday. He is in the terrible stage of being a size 6. Anyone who has had a size 6 DS surely must know how difficult this size is to buy! Kids shoes stop at a 5 in the vast majority of places, and mens start at a 7, and 6's tend to only be available if you order them! I went to a huge city centre Next, and managed to find 3 pairs of identical hi-tops, in 6's. One blue, one red, and one green pair. So bought them all. £66 later, and DS is theatened with severe punishment if they get ruined (and its not really the cost, but the hassle at finding some, and ones that are nice for that matter!). He is not to wear them for football, he has an old pair for that. He can get them dirty, sure. But not ruined! Time shall tell.
He is already in trouble for wearing a pair to his dads who has no respect for anything today, after he asked me this morning, and I said no. I noticed they were the only pair missing when I was putting clothes away in his wardrobe. His dad doesn't care for anything, so he only wears old stuff to go there. Grrrrr. I'll be furious if they are wrecked.
I'm just glad I managed to get them at reasonable prices, as opposed to mens prices for a 10 year old child!!
So, no, in conclusion, YANBU!