I'm not qualified to answer your question, all I can tell you is what I do. I'm up to about 70 Accutrons and it is too much hassle to keep batteries in all of them so, at the beginning of each moth, I select about 6 to use that month and I put batteries in them and take the batteries out of the ones I used the last month. When I get a new one, I get it serviced so I know that all of them have lubricant in them. This seems to work very well.