Hi I have a question about how often one needs to replace the tremolo spring in the back cavity of the tremolo. I have a Fender CIJ 50s Strat with vintage style bridge/tremolo. The reason I ask is because my guitar constantly gets out of tune when I use the tremolo arm. I've replaced the tuning machines, the nut is new and filed according to my string gauge, I have a non-floating bridge with new saddles (Callaham Vintage Fender bridge). All six plate screws are fastened all the way down and the claw is tightened so that the bridge is more or less flat on the body. I have done all I can to make sure that everything flows as effortlessly as possible but I have a feeling that the springs either gets more elastic or that the two screws holding the claw might be eating their way out of the wood (although it doesn't seem like they do). Please, any suggestions is much welcomed! Thanks!