I find the flavor wicks are generally trashed on my first dis-assembly for dry burn. I replace them with one strand of cotton yarn. Wicks well, cheap, readily available.
As far as the coil part, yes, no fixed number of times. If you can't get it clean, or if it pops, change it. Or rewind it. If you're gentle when cleaning, the main wick shouldn't be a problem for a long time. Although, of course, if it won't come clean either, it may be time to change.