Is there a limit to how many testicular epididymal sperm aspiration you can have? or does scar tissue hinder repeat aspirations from happening?

Each person differs.: There is no known limit to the number of successful sperm aspirations that someone can undergo. But the number will depend on how robust sperm production is at baseline, and complications from prior aspirations. Each aspiration does carry a risk of infection, inflammation, and fibrosis. If these processes occur, the success rate of repeat aspirations can drop.