I don't hypermile very 'hard'. I mostly just let off the gas to kick EV on whenever I can..
I get between 50 & 60 MPG on average, and if I'm not climbing the big hill, I can still get up around 70 MPG without much effort. My wife gets between 40 and 50 on ave..
Since we don't drive a lot, the Prius only has about 20,600 miles on it.
Since it's over 6 years old, I finally got around to replacing the OEM 12V battery.
(Had to reset clock, but radio was fine).
Have not noticed any difference in MPG.
Using the old battery for some solar storage.
It might last me a few more years for Ham Radio applications..
I was going to change the oil again this summer, but it's Mobile '1' and I want to get at least 5,000 miles on it before changing..
I did change out the engine and cabin air filters and wiper blades..
The OEM tires still look okay. But I'll bet there are some new tires that can do a little better on snow..
I plan to rotate them again this fall. While thinking about new tires.
For now, we've got the SUV for bad winter weather..