How long do Nikon batteries last?

I have a Nikon D5300 and the battery it uses is a Nikon 27126 EN-EL 14A Rechargeable Li-Ion Battery. Anyone know?

The original one? Around 5 hours of shooting but still it depends on how you shoot. If you avoid monkeying the camera (hitting playback and viewing everything now and then while deleting some along the way) thereby minimizing the use of the LCD (even while shooting), you will be able to extend the life of the battery longer.

Camera batteries aren't rated in how long they last, probably because there's so many variables, such as how often you perform playback, the use of the screen, etc. Camera batteries are based on the number of photos you make and are standardized by the Camera and Imaging Products Association. That said, the Nikon D5300 battery is rated at 600 photos.

On page 273 in your manual, battery life is discussed. Go with the Nikon standard as the CIPA standard is a brutal test. The Nikon standard is closer to reality for a DSLR. If you don't have your manual, download from Nikon's web site.

On my D7000, I get about 1000 shots on a charge which is enough to last me 3 to 4 weeks on a trip to the bush. I only shoot stills and rarely use live view unless shooting studio or macro for critical focusing. The thing that eats up batteries is using the LCD screen. Reviewing photos on the camera's LCD screen, using live view, and shooting video will burn up batteries.

If you're asking the total lifetime of a battery, my D40 battery is still in good shape after 10 years, although the D40 doesn't get much use these days. My D7000 batteries (I have two) are still good after 5 years.

Much longer if you shoot with the viewfinder, rather than the screen.

Any battery will last as long as it lasts --- in other words,
there's no predictable lifetime for them.

Each battery is like an individual person,
with a finite but unknown time to function,
after which it won't any more.

Lol

"Last" as in how many pictures? Or as in how many years before not working well?