Do you try to balance activity cost?

[UnbalancingAct]

Say one DC does an expensive hobby, the other not so much?
One set of GP's pays for hobby but offers nothing for other DC?
Family intend to buy equipment for hobby for b'day/Xmas, but other DC will get "normal" gifts? Do you normally give equipment as a gift or is it just accepted as part of the hobby costs?
Or one DC does 3 hobbies, the other only 1.

Is there an age gap, and might the other child pick up a hobby later on?

I have 2 children and they both do the same expensive hobby.

For us it would all depend. For example if the equipment was needed or just desired, whether it could be got second hand. I don't think there's a right or wrong. However if there were financial constraints then presents to do with hobby seems reasonable, and definitely not saying that B can't do medium hobby because all money is going on A's expensive one. Also though if hobby can become career or not.

I would just buy what's needed at the time. Next time it might be the other dc that needs something or wants to go on a school trip etc.

2 years age gap.
No current financial constraints and other child (at the moment) has no interest in starting another hobby.
Equipment can be rented for a while but it's eventually expected that you have our own.
Child who currently does lots missed out on these activities for 5 years due to constant hospital and other appointments of other DC.