However, you shouldn't have problems with not using a torque wrench on oil drain plugs. These torque specs are very low, 18 to 25 lb-ft in most cases. With enough experience, it's possible to ...

Once the old fluid is completely drained, reinstall the drain plug (and the pan if you removed it). Remember that virtually every fastener on your car has a specified torque rating.

Once you torque the drain plug to spec a few times and get a feel for how much oomph it takes, you may be able to replicate it on your own. But if you have any doubt, use the torque wrench.