I used to leave all my gear on 24/7 with nothing but positive results.
With my Kinki X-M1, I leave it on standby and it works just fine. The reason is, my media stand is tight on vertical space and the Kinki will
heat up to where it actually gets hot.
Others who have theirs out in the open have no problems. So, it all depends.
All the best,
Nonoise