be past your/its best

be past (someone's or something's) best

To no longer be in an ideal state or condition. Many gymnasts are past their best when they are only teenagers. This computer is so slow that it's definitely past its best.
See also: past
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

be past your/its ˈbest

be no longer as strong, fresh, young, beautiful, etc. as before: What do you mean, somebody over 35 is past their best? That’s nonsense. OPPOSITE: in the prime of (your) life
See also: past
Farlex Partner Idioms Dictionary © Farlex 2017
See also: