Since the restring costs me $14 and 48 hours, I can't simply pursue arm-friendly string. Thus, the durability will be the second important factor for buying the next string.
By the way this is the first time to learn about the string. No one (or may be someone) taught me this kind of knowledge. I am looking forward to learn about the hybrid-string set up next time. Also the string pattern (16x18 or etc..)
I am on the court.