Never wack first. I've heard of some guys that do so that they'll be able to last longer when they mow, but at my age, the amount of time I can spend mowing is just fine.
Oh, and If you're actually taking about lawns, I mow first so this way I know exactly what I can't reach with the mower and have to hit with the trimmer.
Oh, and If you're actually taking about lawns, I mow first so this way I know exactly what I can't reach with the mower and have to hit with the trimmer.