4 times so far.
One time because I f*cked up rootfs by mistake.
Two times for upgrading (I think that it is a safe and proper way for upgrading)
One time by a mistake again when I repartitioned eMMC.
@debernardis
wow... haha.. i think no one will beat you...
most of the time i reflashed because i used the wrong command in xterminal and formatted rootfs :P nitdroid is a pain
No need to flash so far, in about 11 months of usage. I once came close, due to some dabbling in extras-devel, but the firmware update to PR 1.3 solved that problem.