THOUSANDS of videos...
I even have a rating scheme, because there's so many videos I can't possibly watch them all each time I masturbate: a file name starting with AAA means its very good porno and I should jerk off to it again

i also go through phases; sometimes i'll jerk off to a few particular videos for a week or two, then they get old so i switch to a different group of videos, then after like half a year the first group of videos is appealing again so i go jerk off to them again