Posted: 27/07/2017 at 14:05
Some plants prefer to have their roots constricted. The usual signs which tell you something needs re potting is a general deterioration of the plant, Roots pushing out of the pot ( top or bottom), etc.. If you suspect there is likely to be a problem, best to remedy before your plant suffers. Leaving it until it looks unhappy means it takes slightly longer to recover when re potted.
Easiest way is to remove it and see if it is really rootbound and therefore little room for the potting medium. If the pot is full of roots, then a size bigger should see it right.
Only you can tell I'm afraid