You'll find plenty of opinions and advice on this one. But keep in mind: any wet or gooey lube inside a pin cabinet or head will attract and accumulate dirt (especially solenoid dust) over time and eventually gum up and/or dry out/solidify. I've been rebuilding steppers and moving parts for 13 years and have had the best results with dry teflon spray -- after a thorough cleaning with alcohol and 600 grit emery or paper. The waxy PTFE powder clings but can't hold dirt. I've never had an issue with stepper performance after a rebuild. I see it as the happy medium between Teflon gel and no lube at all. Be careful, though: it leaves a white residue anywhere it lands, so take steps to avoid overspray. Just my opinion, of course.