as far as I know, the REM period lasts only 10 to 15 mins. So, one LD could only last for maximum 15 mins. My LDs period is usually between 5 to nearly 15 mins.However, in a dream, sometime I feel it lasted for very long times, maybe 1 hour.

So, how long is your LDs period? do you know anyway to lengthen the LD period?