As the title says, I'm late to the party. Never really read this article that TWU published so many moons ago. http://twu.tennis-warehouse.com/learning_center/deadstrings.php Specifically, the conclusion part: "The data provides evidence to support the speculations of many players on the causes and perceptions of polyester strings going dead. The lower tensions and perpendicular stiffness of many polyesters leads to longer dwell times and greater deflection. This keeps the ball on the racquet for a longer arc of the stroke, potentially creating "power" problems with the ball going deeper, wider and higher than desired. The decrease in perpendicular stiffness also contributes to the sensation that the strings get "mushy" or behave like a trampoline. A loss of control is the end result. Further, the stroke itself may thus be affected to compensate for the changes in the string." They are basically saying that there's this "magic time frame" of a couple of hours where polyesters perform to their peak potential. But then, once the poly begins to "die", they start to exhibit particular characteristics that lots of players all across the board have anecdotally described in some way shape or form -- but finally the TWU was able to prove it with SCIENCE! Anyway, I guess what I'm saying is this: If you want to keep poly strings on your frame for longer than 8 to 10 hours, you'll experience one or more of the following string characteristics: More power Less control Higher trajectory off strings Increased stiffness The key thing about this is, if you had bought strings that specifically marketed themselves as having these characteristics, then you wouldn't be surprised one bit if that's what you got. BUT, You didn't. The typical TT forum member or joe schmoe off the street buys poly strings for the following characteristics: Low power High control Low trajectory off strings Increased spin So when he or she buys strings expecting these results -- and gets them for a couple of hours -- is very annoyed that it all changes after a couple of hours. Especially since these strings are never marketed that way. These string manufacturers never advertise that it's a short life span, that there is nothing worse than dead poly. OK, so off my soap box. In my amateur point of view, I'm thinking that going full synthetic gut may prove the best bang for your buck. I know, I know, a lot of you have stated this already in many, many threads. But not only am I starting to agree, I'm also starting to think that it has more to do with that. Not only will nylon strings last longer (mono or multifilament), but their characteristics change less. Nylon strings don't become a completely different string after a few hours of play. As nylon strings die, they: Move around a lot on the string bed Begin to fray Eventually break This list is my experience of a typical nylon string after 20 to 30 hours of play. Sure, you could say that some nylons exhibit more problems after the 40 or 50 hour mark, but honestly -- you've gotten your money's worth by that time, and it's more likely to break before you get that far. And, don't even get me started on tension loss of poly versus nylon strings! Conclusion Unless you are very wealthy and can afford to leave your poly strings on for less than 10 hours, then not only is poly a waste of money, but it can actually hurt your game and your growth as a tennis player since you have to modify your game, your strokes and your technique to compensate for the string's eventual death march. As poly dies, you are changing almost every aspect of your stroke to keep up with the way the string changes. And, if you're leaving your poly strings in for longer than 10 hours, you could be doing damage to your arm since it becomes so stiff. If you go nylon, you can remain more consistent across the life of the string. You don't have to change any aspect of your play from 0 to 20 hours of play time with the string. And, you can leave the strings on longer without any negative consequences.