Around ten is a fair number if they span your interests in terms of caliber. A lot depends on if you hunt or not and what you hunt.
If you get the 22 rifle bug, it is easy to have ten of those depending on your shooting interests.
I have not purchased a new firearm this year. There are a couple I keep my eyes open for but have not been actively searching. I like to let fate influence what firearms I purchase and when. Keeps it interesting.