I have Andy Rooney eyebrows.

Every month or so I trim them by running a comb "backward" over the brows, trimming every hair that sticks up beyond the comb.

I also pluck between my brows, choosing the victims by scowling and then yanking out every hair that sticks straight out from my skin when I scowl. It is asymmetrical, but it ends up looking just fine because my face is somewhat asymmetrical anyway. I also pluck wayward critters that are creeping south of the rest of their brethren.

My mom has had her brows threaded, and loved it. She says I should do it, but I'm quite happy with my own (free!) monthly maintenance program.