Up until the PSR-3000 became available I used two keyboards, once of which tipped the scales at more than 50 pounds. Several years ago I posted a photo of the rig on this forum, which took nearly 45 minutes to set up--WHAT A BEAST!
When the PSR-3000 became available I began paring things down, including the number of keyboards. It was the best move I've ever made. While playing with two keyboards provided a security blanket, in reality I have never had a complete failure of any keyboard in all the years I've been performing. So, now it's a single keyboard and a laptop for a backup system--just in case I were to encounter that first-time keyboard failure.
Cheers,
Gary

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PSR-S950, TC Helicon Harmony-M, Digitech VR, Samson Q7, Sennheiser E855, Custom Console, and lots of other silly stuff!
K+E=W (Knowledge Plus Experience = Wisdom.)