It will save the life of a battery, if like we do store a few months, plus keeps from always disconnecting the battery cables. Before I got one, I always left mine hooked up to the battery, about 3 months of none use I would here a beeping noise in the camper, it was the low battery warning beep, I put one on right after that and turn the switch to off when not using, on our other camper, I had the original battery for 6 years before replacing by doing this.
Tal and Debra
2016 Forest River Surveyor 251RKS
2003 Chevrolet Silverado
2011 Chevrolet Tahoe