I just keep going, no matter what it costs me. - 50 Cent
I made the above basketball training video in 2009, in which I told viewers to do the prescribed drills daily for 5 years. Still to this day I get the question, do we really have to do it for 5 years? Actually you don't - you have to do it for as long as you wish to be good.
And Ball Is Life, right?

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When it comes to your definite chief aims in life, i.e. your most important goals, there should be no timeline on your success. You keep playing the game until you win.
Many who reach out to me ask me how long is "average" for attaining some level of success or making such amount of money or being a certain level of competent, and it doesn't work that way. I know what causes these questions, and they're all interrelated:
Concern over how others will perceive them for not achieving a goal in a certain period of time
Fear of being told to quit or give it up, with a passing of time being cited as proof of failure
Lack of definiteness of purpose, which makes it easy to walk away from anything that doesn't produce immediate results
Lack of mental toughness, which persuades more people to quit on their own volition than a hundred naysayers could
Whatever you decide to do with your life, you have to decide on at least one thing for which the clock never runs out -- actually, there is no clock. You go after it, changing strategies when necessary, until you get what you came to get. The game ain't over until I win.
Just make sure you 1) Know clearly what this aim is and 2) Know how you'll know when it's been reached.