Luxilon strings

I am very happy with using the Luxilon Big Banger Timo strings in my racquets; but am not sure how often to have them restrung. With two racquets being alternated and playing 5-6 days a week, I have been playing with them for nearly eight weeks now. As advertised, they show no sign of wear and I really cannot sense the ball ‘flying too much’ off loose strings. So, how often should you cut them out and replace them?