5-10 /year and would go more if :
I lived closer to my favorite venues (those that put shows on I want to see) I can get tickets without stress (π to ticketmaster, scalpers, etc)
I like loud but there is a thing as "too" loud. sound engineers know what they're doing. For these shows I use the foam plugs
I do buy merch. I like music. Others who do should go and be a part of your community, both physical and cultural. Make an effort!