Re: leaveing the a/c on
Back in the years of early AC compressors, premature damage could happen to the compressor. Times have changed and so have the clutches on compressors. For the better! Once the compressor stops turning and the ignition is powered off, the clutch disengauges. Upon restart, the clutch doesn't engauge instantly. There is a delay before it happens.
I don't think I've ever turned mine off in my 2.5 years of ownership. My climate control stays on auto. Vehicle gets started quite a few times each day.