Every day of my life I see football players. Some of them as they are going to their training sessions and others as they're leaving the pitch to go home and have a good rest.
But then there are players that are on the pitch all the time they can. They usually come early to the training ground and work individually. They practice the things they need the most. For some, it's dribbling or shooting, for others, it's joggling and improving their first touch. In football, like in life - there are lots of things you can improve on all the time. Once you stop improving yourself, you've lost the point and it's sure as fact that some other player will take your place in the squad.
There is always a room for improvement!
Even players like Messi or Ronaldo work their asses off because they know that the only way to stay on top is to work hard and dedicate yourself with all your heart to the thing you're doing.