Leaving powered sub on all the time.

[Rob J in WNY]

Leaving your powered sub on all the time will likely not harm your sub, although some people might think doing so is a potential fire hazard. Of course, it's easier on the electronics if it does shut off. Why not just use the "Auto" setting? In "Auto," your sub's power is triggered by an incoming audio signal from the receiver, and shuts off when no signal is present for a little while.

To be sure, some people like to turn their subs on and off completely manually as well.

Absolutely do NOT use a switched outlet on your receiver to power the sub. Switched outlets which are built into electronic devices are fine for operating low-power devices such as disc players, cassette decks, etc. Your subwoofer will certainly draw more power than your receiver's switched outlet is rated for.