It depends on the balance between maintaining authenticity and maximizing revenue. A good rule of thumb is:

•1-2 per week (4-8 per month) if they align well with my content and audience.
•More than 8 per month only if they’re high-quality, non-intrusive, and don’t dilute my brand.
•Less than 4 per month if I want to keep my content as organic as possible and avoid sponsor fatigue.

It also depends on the type of sponsorship—dedicated posts, shoutouts, integrations, etc.