Yes they break down over time which is not a bad thing for some players
Del Potro did not like the "new" frames Wilson made from his old mold a few years back. Same with James Blake.
For me. anything under 150 cycles of re-strings / frame I can not notice 8-B
End of Play test report
String received Tourna Deuce 17
Tension(s) used for play-test 44 lbs
Current String set up Bear Claw 1.20 mm, I switch strings a lot
Racquet used for test : Prince O3 Speedport Gold 110
Power/Control of test...