it depends on the tea and at what point you get tired of resteeping.
depending on the tea it can be anywhere from 1 steep to 20-30 steeps.
Most teas you can get 1-3 really good steeps and then depending on the tea steeps # 6-8 will still have good flavor but may be significantly weaker.
I brew my Kagoshima Sae Midori fukamushi usually about 6 times.
I brew my Formosa oolong about 8 times.
I brew my Organic dong ding about 10 times.
And a mystery oolong usually gets about 6 steeps. With this one sometimes i add an extra half serving of tea after 6th steep to boost flavor and then brew it to steep 12 or so.
It all depends on where you want to give up, after it starts loosing its flavor and turning weak? or after it literally tastes like plain hot water? its all up to you and your taste buds.
you can resteep everything but matcha!