Common sense applies.

The heatup/cooldown cycle can take its toll on electronic components and connections as well, so if you go away from your keyboard temporarily during the day and are coming back to it again, you should likely leave it ON for those short periods. Of course, if there is the threat of a lightning storm, you should turn it off and unplug it from the AC mains anyway.

--Mac

My instruments (17 keyboards on and off) and computers and other equipement last time was
turned off probably in 1999 or when i sell them and replace them with other instruments.
I go to work, vacation, familly, sleep, watch a movie...everything stays on...and the E. bill? OK!

Most keyboards today are merely computers. If we take the computer approach, most computers today that run in a Data Center are powered on 24/7/365. We perform yearly power down tests to ensure none of the computers fail on the power up sequence, test the quality of the power filters, and replace battery backups.

I would recommend a good power conditioner (the ones that have a backup battery in them) to protect your electrical circuit from voltage fluctuations which can kill electronics. JMTC

Al

I have left my Yamaha on for 6 hours at a time hundreds of times for gigs for the past six years without a problem.

But Nedim, did you turn them on after 1999?
If so don't say it too loud because ignorant people like me would never buy an used keyboard that has been turned on since it was bought!!

No joke, this thread surprised me a lot, I turn on/off all my equipment 2 or 3 times a day whenever I have some time to play.

Much of my equipment is connected by wires - TV aerial to computer, Tyros(USB)to computer, phone/router/broadband to computer so if there are electrical storms about or if I go away, the TV aerial is unplugged, the phone is unplugged (overhead lines being vulnerable) and mains supply to all the expensive equipment is unplugged. (It multi-sockets from one mains socket so usually only 1 plug has to be pulled to do the trick).

john