I have a restored Pepsi-Cola Jacobs 56 soda machine that i do not run very often, about twice a year for a few days each time.  I am concerned that the refrigeration system will not be maintained properly by running the machine sporadically but do not fill or use the machine as i use a restored Vendo 81 running full time for this purpose.  What is the recommended approach or experience?  Should the machine be run more often or can it be run 1-2 times per year to keep it mechanically healthy?

Thanks for all of your thoughts in advance.

My machine has a decal above the coin chute that states: .10, Use nickel dime or quarter, change returned below.  Is this the decal you are looking for. I have attached some pictures.

Once or twice a year should be fine,  just to keep the moisture out of the controls and any bearings in the fan motors from drying out. Really once a sealed unit is sealed and there aren't leaks in refrigeration system, it does not need to be ran every so often.

Thanks for everyone's thoughts--a few times a year sounds fine and seems to make sense.