I've been a Walkera UFLY owner for a while now.
But running servo range checks and bumping into hallway walls doesn't really count as flying. I already gave it a minor crash once and broke something — seriously, don't fly in tight spaces, it almost always ends with a snapped carbon part.
I finally brought the helicopter home properly. On Friday and Saturday I tried to balance it as precisely as possible. I mostly managed it, though there are still small imperfections. That's why I only flew it up to 2.5 cm off the ground! Hopefully it'll go higher next time :-)