Have seen/known better days
Definition 1 of 2
Pro Tip 1/3Objects’ Condition
Use when observing that objects are damaged or show wear from use or age. 
Her family heirloom has seen better days; it's quite tarnished now.
Pro Tip 2/3Time Reference
Implies comparison with a past state where the object was newer or functional. 
This old train station has known better days before the modern terminals were built.
Pro Tip 3/3Not Literal
It's a figurative phrase and shouldn’t be taken to mean seeing or knowing days literally. 
This sofa has seen better days; it's an expression, not that it actually 'sees'.