Question about Prius Battery

Hello! I have been wondering about how much longer our '09 Prius is going to last. Here are a few factors to consider.. how many more months/years do you think that this car will last?

• It currently has 112,000 miles and we live in a semi-rural area, so a lot of mixed driving. It's mainly used for commuting to work and back on most days (5-10 minute drive) and running errands within town w/ barely any highway driving.
• It has been starting to idle a bit louder when we cold start it (a little bit more vibration and noise/rattling coming from the Atkinson) and I've read that that's a sign of possible battery degradation because the engine has to work a bit harder to get the engine to operating temps. We also heard some unknown rattling noise during medium acceleration from 15-30 MPH, just to throw that out there.
• I have noticed that the green status lasts a decent bit shorter (around 2-3 miles if I drove it at 35 MPH with the battery only going to the tires on the infotainment screen), but I do hit full green status a lot more often.
• We have noticed some erratic MPG ratings this past few months, it would go from 50-65 MPG to 40-45 on the next fill-up afterwards (our fill-ups are usually within 200-400 miles of consumption), with the same person/2 people driving it normally in similar conditions.
• We have replaced the smaller 12V battery in the trunk around 2 years ago.

Should we expect the big battery to possibly be replaced within the next year? I have heard that the avg. lifespan is around 10 years, and the mileage does not matter much as long as you put it in those 10 years..

 

Alright, thanks for the input. Our mileage is pretty average, we've had the car since 60k miles in 2012 I believe, so we have put just over 50k miles on it, which is not a lot at all. I'm sure that re-cycling through the battery repeatedly is probably better since inactive cells could destroy their battery capacity, just like leaving a phone off for several months.

 

Okay, thanks! I have heard about third parties being able to replace certain cells and such, and yea we probably won't go to the dealership because they always inflate their prices like crazy. We'll look into the battery pack reconditioning since we are trying to keep this vehicle for a long time. Thanks again.