One of my front brake calipers is sticky and needs to be replaced. What else should be done while the caliper is out?
No, if the rotor is in good condition – no grooving and thicker than the wear limit – there is no need to replace it. If it is marginal, scored or almost down to the wear limit, then it would be a good idea to replace the rotor.
The other think you want to look at is the condition of the pads. If they are significantly worn this would be an easy time to replace them.
You can get the rotor resurfaced if it is within spec. The problem with putting the thing back on is there is an eccentricity ground on the surface that acts to push the caliper open when the brakes are released. This gets worn down with use, so it should be restored at each brake change. Most decent auto parts stored or any auto machine shop can do it. Probably costs $15 each or so.