All options decay over time. You can't hold an option for 10 years. In fact, the time decay of an option increases exponentially. The less time left on the option, the greater the effects of time decay.
Due to the large amount of time on LEAPS they depreciate slower than traditional options. It will take a LEAP with 3 years before expiration 273 days before it will loose 20% of its value due to time decay. At 180 days before expiration it will take only 65 days to loose 20% of its value to time decay. Finally at 81 days before expiration it will take only 30 days to loose 20% to time decay.
The effects of time on a LEAPS are minimal. This is what makes LEAPS so attractive to trend followers.