Thank you for giving such an interesting question I'm going to be pretty quick about answering...humans go through about 3-4 sleep cycles each night but we will assume four...we get dreams in REM sleep which last 20 minutes per sleep cycle...2o minutes of REM per cycle for 4 cycles gives 80 minutes of poetential dreaming in one day...80 minutes mulitplied by 365 days in a year give you a potential to dream 29,200 minutes in a year...If the average person lives until they are 80 years old, then we can muliply 29,200 minutes by 80 years to give a potential of 2,336,000 minutes dreamed in a lifetime...divide 2,336,000 minutes by 60 minutes in an hour to give 38,933.3 hours and divide again by 24 hours in a day to give you 1,622.22 days and divide by 365 to give you years which would be 4.44 years...IF A PERSON LIVES 80 YEARS THEN THEY CAN DREAM FOR A SOLID 4.44 YEARS IN THEIR LIFETIME...