I hit the device limit constantly on iTunes and have to declare "bakruptcy" (unuauthorize all devices) to reset it. This is what happens when you have a laptop, a desktop and work and home, a gaming computer, and things like a media centre computer.

I have never once hit it on apps.

That does not make sense for the Mac App Store. Mac Apps will only run on a computer.

Can you get around that using family share?