Perf comes in a few forms:
Monomeric (cheap) perf used to be rated for 1 year but now everyone who makes it claims two years. I believe they do that mostly betting on the fact people won't bitch if it doesn't go for 2 years. This product is cheap and great for shorter term perf applications. As most of you know, it is an absolute bitch to remove after 6 months as it will break into tiny aggravating slivers at removal time.
Polymeric perf is usually rate for 3 years of performance. It costs about double and even after years of application, it will remove in much larger pieces.
PET and cast perf can perform for 5 years....also removes much easier.
learn more at
www.cgxusa.com and you can study the Panorama One (monomeric), Innova (polymeric), PET (green), and cast. The same is true at Contravision....their Campaign is a shorter term and their Performance is their long term.