I've been trying out several different polyester strings lately, and I'm trying to measure how long it takes them to go dead, since most of them play similarly and the length of time during which they stay playable is one of the most important factors in which one I choose. Since my hitting schedule is never concrete, I don't know if I'll hit for a week every day or if I'll go two or three days without hitting. I'm wondering if these strings get closer to going dead even if I'm not playing with them. Simplified, my question is what determines how long it takes polyester strings to go dead; the amount of time they are in the racquet, the amount of time you are hitting with them, or both? Note; I'm saying 'go dead' as in lose their elasticity, not to be confused with tension loss.