Considering that they spend so much time next to my face, I think I'd opt to replace. A few cents more on safety beats th hell outa thousands of dollars given to "Ol' Saw Bones" IMHO.
I don't see me ever reaching so close to a batteries limits, but, Id still want to have the most kick ass batteries, with respect to power, and safety that I can get.
As long as I know the limitations, I'm good.