How do you keep the trailer backup battery charged. (or do you)

[the old grind]

For decades there were guys who would only change the oil or a filter but not both. I'm sure they had their reasons. I also remember tube radios and 6v systems with rubber/cloth-jaketed wiring under the dash from those high tech days of carburetors and 4-wheel drum brakes. #WhenOldIsNewAgain

 

[bigtiller]

I worked in a full service gas station back in 69 & 70. It was common practice back then to change oil at 2000 miles and oil filter at 4000 miles. Times sure have changed.

I remember the push to use TP as an oil filter. I never bought into it and never seen one being used.