I dont really have any other hobbies that arent car related really, which is a bit sad in a way I guess!
I spend probably 15-20K ish a year on cars (half that doing trackdays and half on buying and modifying cars and taxing and insuring and MOTing them all etc etc), but historically Ive covered a fair chunk of that with spending my spare time doing motoring journalism, which probably covered about 1/3rd of it, and in the past when I was doing a lot more mapping of cars for people that probably topped it upto well over half that, so it was kind of a self financing hobby in a way. These days I dont really have enough time to do those things much at the moment for the extra income but on the other hand im working more in my main roles so my wages are good enough right now that I can comfortably afford it anyway, so I still dont feel too bad about it not paying for itself as much anymore.
Luckily for me my mrs enjoys all the trackdays just as much as I do, and so she pays a lot towards them from her wages too, so that helps as well, although the down side is that means yet more cars on the go at once so more maintainance and modifying etc so even more time gone, but lukcily she helps out with the spannering anyway so it sort of balances out (she fitted the RS2 as well as buying it for example)