I do use a torque wrench. Steel bolt, aluminum pan, I'm always worried about stripping it. Have I installed one without a torque wrench in the past? Yes. But I have a torque wrench in my toolbox, and it takes maybe 30 seconds longer to get it out and use it, so, why not?
Incidentally, be very careful with transmission pan drain bolts. The pans are usually thinner and the holes have fewer threads than oil pans, so, they can be easier to strip. Ask me how I know.