When my two D3-era EN-EL4a batteries died, I got a brand new Nikon one to continue to be able to use my D3X. I don't use it a lot, but do use it as my primary studio camera (all the settings are dialed in, so I just pick it up and shoot); the ergonomics are great, I shoot at ISO 100, and I don't need a newer camera for this purpose. I figured if I can get 5-8 more years out of it with the new battery, it can then be retired. ;-)