When feeling the surface of my rotors, I can feel a little bit of groove, but it's pretty subtle. Should the rotor feel perfectly smooth or is some surface variation expected/acceptable?

There's usually plenty of variation on any used rotor. When the decision comes down to turning or replacing, however, replace. They're pretty cheap to buy, probably cheaper than you'd be charged to turn them. You do have to include the price of new front wheel bearings, however, since the rotor IS the bearing carrier.

Thanks. I'm working on replacing the front wheel bearings today and thought I should check out the rotors.

The cost of turning is just a LITTLE less than new ones.

Rotors are fine with a few grooves. As long as it doesn't look like Keith Richard's face or like the pads went to metal...yer prolly fine.

depending on how thin they are, you might not have the option of turning...most shops will not turn a rotor once it's reached it's min. thickness

as copied from Pelican...