Leave amps on or off?

For my solid state amp I switch it on al least 1 hour before listening, my experience with 3-4 hours before is better sonic quality as Garfish's is . Also consider that you might have spikes and brown outs that have to be added to the equation and don't take out storms and lightning possibilities. Shure you should have some protection but remember that some filters, etc do compromise dynamics as in many areas in this hobby you take your considerations and go with the best compromises that you choose.

I have recently started leaving my SS ARC 100.2 amp on all the time, and I can tell you that the sound is MUCH BETTER! I have a tube preamp which I leave in standby mode when no being used. Of course once the preamp warms up the sound is even better, but by leaving the amp on all the time I am amazed at the improvement.

I have always left my solid-state amps (Adcom, Bryston, and others) turned on at all times (except during electrical storms, or when away on vacation). Over a 13 year period, I have only one problem that required repair (a power transistor burned out). I think solid-state amps sound better when fully warm, and the warm up/cool down cycle is harder on the amp than being left on all the time.

What is the life span of the green diode indicator for standby/left on position. Has anyone had to replace them due to their units being on all the time? Thanks

I always leave my sold state gear fully powered up. It takes at least a full day or so to peak from a cold startup. Thermal cycling reduces equipment life, which is another consideration beside the higher electric bill. The energy isn't really wasted (about 9 months of the year it contributes to household heating) & power is cheaper in the midwest nowadays than natural gas anyway.
To "7671" your LED's can actually last longer than you will.