I was wondering when people replace your actual camera batteries (as opposed to replaced the battery in camera)? Do you wait for them to die outright? Is there any harm in continuing to use them even as their recharge performance dwindles?

My story, I have 3 LP-E6 batteries. One that came with my 7D, one with my 5DIII and one I bought as a back-up in 2011.

I set one aside to sell with my 7D (a friend wants to buy it but we are waiting) and I marked the battery I received with the 5DIII.

On my Florida trip, I noticed that one of the batteries that are from 2010 or 2011 (not the 5DIII battery) finally dropped to the single red bar in "recharge performance." This is a first for me. I continued to shoot with it and went through ~700 shots with plenty review time before it needed recharged again. So, the performance is still good.

So far, with all three LP-E6 batteries, my experience is that they pretty quickly (couple of months) went from 3 bars of recharge performance to 2 bars and stayed at 2 bars for years...until now.

I always carry a backup battery, so I should be fine. But I am tempted to discard the battery that has 1 red bar recharge performance and replace it with a newer battery.

Thanks....