As the owner of a training agency and with diving safety as our first and major priority, I have tried over the past ten years to get a "Time Limit" based on experience into our system, but it has always been blocked... My idea was to have those divers who dive less than five times a year for cards to expire... and those who are diving more than five dives a year will continue to remain "Certified"... Technical divers, CCR and CAVE in particular need to keep their skills sharp to remain safe and would have 2 year certifications... Please share your thoughts...