It comes with a balance knob?!?! I'll take it!

I make a headphone amp with a balance  control. I had one customer ask for it just because he thought he needed it, and another that has a hearing problem in one ear. Depending on what he's listening to he has to adjust balance. 

Turned out to be a bit of a selling point.

Balance control makes sense even if hardly ever used in my case. It is God sent for hard of hearing in one ear, and may even be advantageous for normal hearing folks to better center the sound on some questionable recordings. More options is always a plus.

My main rig has no balance control. I only use it for critical listening and I sit in the sweet spot.  I don’t need a balance control for this.  I have a second system in the room that I use for casual listening and am always sitting somewhere other than the sweet spot.  The balance control on that one is critical.

It comes with a balance control?!? I'll take it! Apparently said by many!

Like many here, my hearing is less acute in one ear than the other. Without a balance control the stereo image is always naggingly off center to me.