The above explains that Li-ion batteries do wear down and manufacturers have ways to quantify that weardown. But are there any hard stats for Treo batteries? (ie, 20 pct capacity loss after 200 charges from 50pct to full?)

I thought I read somewhere that a battery loses 25 pct of its capacity for every 500 charges from half to full.

I ask for two reasons-

1) I've been using a pair of 2400mAh Seidio batteries for the 700wx for almost 17 months now. In that time they have probably gone through

17months x 30 days/month x 2 charges per battery per day from 60pct = 1,020 charges each

So if I'm less than happy with my 700wx battery life, maybe it would help to get some new batteries. Maybe they're peaking at 1600 or less now, based on that formula.

2) I can expect 4 such charges per day on my 800w battery, so I might be working with a 700mAh effective capacity battery after just 8 months. How often should you replace the batteries?