Depends on the tea.

We have a local gathered tea (sold on stores in Manitoba), made from nettle, goldenrod, and labrador tea. That one we could steep for days if we wanted to, and it only gets better.

My SO likes to add sour fruit in the last minute, after a long steep. Sometimes lingonberry or buckthorn or something, to make it super tart. It's like turning tea into sangria haha.