My Generac was floating my AGM way too high. I bought a Battery Tender, use it to charge, then drop the voltage for float.
I have an optima yellow top that is 5 years so far on it.
Do the oil changes yourself like ^^. They are easy and cheap with Fram or WIX filters. I run Penz 5w30, same as my truck so always have a lot on hand.
Yep change the oil myself, and stock a lot of oil and filters. Have a good amount of the OE Generac filters from buying a few maintenance kits I got a good deal on, mainly for the air filters
But, I have a few FRAM Ultra Synthetic filters too, much easier to change because of the rubber grip