I need your help and opinions. Strung up RPM Blast 16 in a Wilson K90 at 47 lbs and went out to play a 5 setter. The feel was PERFECT for me. Perfect amount of pop but zero trampoline. Linear power, no surprises. With my regular windshield wiper forehand the ball climbed up a yard to two yards over the net on every ball with magnificent directional control. Wide slice serves to the deuce court were VERY wide and opened the court nicely for a flatter down-the-line forehand deep to finish that particular play. Fairly plush feeling for a poly. Played 5 sets over 4 or so hours and i won 4 of the five against a speedy aggressive player. Did the racket feel the same in the fifth set as in the first set? No, it did not. Grade: A+. THE NEXT MORNING at 8am, i was out on the courts against a NTRP 5.5 aggressive player. I had just beaten this man 3 straight times over the last 3 weeks playing with a different K90 strung with some tired but expensive poly. I expected to leave the court with his head in my 12 pack bag. We began the warm up. ....What the f)&#? No pop, dead feel, wooden feel. Was I tired from the day before? What was wrong? Was there something wrong with this can of balls? I opened another fresh can for the start of the match, because something was way wrong. I was having to muscle the ball. If i have to put it into words, it felt like the springiness response of the string had SLOWED. The racket felt paddle-ish. Yesterday's effect of the ball climbing up over the net and then dropping was just gone. No matter how fast i swung, i could not get the same beautiful ball arch on the ball that i had achieved easily in rallies the day before. The day before i felt that I could do anything I wanted with the ball, and today i was struggling just to not make errors and to keep the ball deep. Anything short and this guy was all over me. I won the first two sets and lost the last 3 by a break each. I tried my best but with a guy this good, a short ball from me and he had me on a string. Where I had been cruising and playing my game, today I was struggling to keep errors in check. My serve was down by about 10mph and far less spin and so less control. The wide ones were not wide enough so they went right into his forehand strike zone and he could do whatever the f)*# he wanted. Here is my question: What string will give me the effect of a fresh full bed of RPM Blast at low-ish tension but will last at least a bit longer? Or am I now a cocaine addict and if I want the high I just have to pay the piper and string this stuff twice a week after every 5th set? (to be honest....if it was a tournament I would change to a fresh RPM Blast job after every 10 to 12 games). I have never in my life experienced this noticeable a drop off in performance OVERNIGHT. In all seriousness, if my life was on the line to answer the question "is this the same string that was in your racket the day before?" i would have said "no, it is not the same string i used yesterday."