How often should I remove the charger from my rMBP?
Quick Answer

Modern batteries, including the ones Apple has used for over a decade, don't need the type of "conditioning" you're talking about.

As a rule of thumb, when you're near an power adapter, plug in. If you're not near one, work off battery power.

There's just one exception to this rule: don't leave your Mac plugged in for long periods at a time, say, over a week. The battery needs to exercise, and if it's plugged in for a really long time, it might "atrophy."

More Details

If you tend to leave your computer plugged in all the time (for example, if you leave it on a desk all the time), get in the habit of unplugging it every weekend. It doesn't need to drain to 0% each weekend, or even close to it. Along this same line, if you're leaving your computer along for over a week, just leave it unplugged.

The one-week timeframe is actually a bit over-cautious, and no harm is likely to occur even if you left it plugged in for two weeks. (Apple's batteries are the best on the market as far as taking care themselves.)

Sources


I'm an Apple-Certified Mac Technician, trained by Apple
Apple's public website: http://www.apple.com/batteries/notebooks.html