I guess the best thing is to empty the cams on not have a partial roll in it.
Yep. Rewind, leave the leader out (35mm) and write the number of exposed frames on it, put it in a film can. When reloading, put on the the lens cap, (and for maximum safety, set the camera at the fastest shutter speed and the lens at smallest aperture). Advance to the number of frames recorded, plus one. Or plus two, if you're really concerned. Before reloading, check the film leader for any crud on it, to avoid scratches.
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.