When playing at home, I have it on 0.5 watts nearly the all the time, with an occasional visit to 15 watts if I want to get crazy. When jamming, rehearsing, playing out, usually 15 or 45 watts. So 90% of its use time has been on 0.5 watt.
I have owned my BCA for close to 4 years now. I have cycled it between 0.5 to 45 many times. I mostly play it on 15. Also, I have left it on for a few days at a time, although not often. It has been super reliable for me. Granted, it doesn't get gigged....maybe a loose connection somewhere...I don't really know how complex these amps are...especially with the tone capsules...are many techs versed in the workings of a BCA?This is just a theory, I don't "know" electronics... but I wonder if the power attenuation feature actually stresses the power supply. Like, it would be better off to always leave it at 80W and just turn down.... I play mine with my band exclusively, and it stays on the 15W setting... but I wonder...