Looking for the definition and then starting with "I personally"? :D
Replayability is pretty concrete. If someone likes a game that much that he comes back to it after beating it - but "beating" a game is a loose term. Is it playing all levels, seeing the ending credits, earning 100%?
Replayability can be:
DLC
online
different endings
different characters
daily rewards
achievements/trophies
...
the list is way longer.
All of that only applies when someone really likes a game, though. Why would anyone play a game again if they don't like it? Yes, achievements/trophies but those people are a minority, a very small one.
I "replay" games I like. Even if it's just one level, going for the highscore.
Of course, there are games that never officially end (except for lame credits after hardest mode or whatever) so they are endlessly replayable. Mostly party games.







