I try to do one major project per year that costs between $5-10K. Minor maintenance issues usually add up to an additional $1K per year.
Last year I had my engine transmission rebuilt which cost $6K.
The previous year, I ground out and patched hundreds of hull gelcoat blisters and epoxy barrier coated. I took time off work to do the job myself, so technically it cost me lost wages, but around $3K in supplies. It would have probably cost well over $10K to have a yard do a half-ass job.
This year, I'm planning on replacing the rig with $10K budgeted.
I'm aiming to drift more toward $5K per year once the vessel is shipshape.
(Also, $6K or so on marina fees.)