However much we all wish that our favourite fighters could stick around and continue to kick ass at the top of their game forever, it's inevitable that they'll all choose to call it quits at some point.
Consistent injuries, growing old, a damning losing streak or even feeling the need to pursue interests outside of the Octagon have all paved the way for exits from the UFC in the past.
Yet, anything is often possible in the world of MMA and over the years we've seen many a seemingly finished fighter make a spectacular U-turn and return to prominence - with varied levels of success.
We've already seen Conor McGregor make a successful return to the cage by sparking out Donald 'Cowboy' Cerrone in less than a minute at UFC 246 this year, so will another fighter follow in his footsteps and re-establish themselves in the current 2020 UFC landscape?
Nothing is guaranteed in the world of combat sports. But, these ten fighters have all been sitting on the sidelines for long enough and a comeback in 2020 could very much be on the cards.
Just when you thought 2020 couldn't any bigger, eh?