Quad 2905

I recently had my speaker panels repaired. I'm getting mixed information about weather the speakers should be shutoff when not in use. Some have advised me that keeping them charged all the time will cause early failure.
I thought the original speaker, aka the '57 required a constant charge- and that the later models didn't. But I can dig down a little. 
Are these the models that were manufactured in China? There's another recent thread on here about panel failure due to the glue. 
I used to keep mine- both the '57 and the '63 plugged in 24/7 but different speaker. More if I find an answer or if someone else with knowledge of this Quad posts here. 
Yeah, typos, the bane of my existence.  And auto-correct makes it worse sometimes....