it's bepond on:bending Radius, Bending Angle,Bending Length, Bending Rate Beding Position Must Be laminating coverlay
Some bending test Maybe even 100,000 times
Better plate limit test on the market such as flex bending times shengyi 100~150,Panasonic 150~200, DuPont 200~300 times.
So you will find that flex boards of 10-30 dollars are now appearing on the market. The boards used are much lower than those made by shengyi Panasonic and DuPont.
The above number of bends is only from personal experience