When do you retire your LIPO?

[brainanator]

gens ace are great, and I usually have good luck with turnigy too. Some of failed a little early on me, but I don't mind too often, I could be paying 4-5X the price for lipos.

You run your batteries down to LVC all the time? That could be affecting their lifespan if is set too low. I run mine at 3.3 or 3.4V/cell. And if you stop before that your batteries will be all the more happy.

As far as your IR concerns, I have no idea really. Maybe try different resistances and average the IR. Not even sure if the equation is correct, but the dimensional analysis returns ohms, so at least it's the right units! I know some chargers will tell you the IR of packs.