Since I mentioned it in the "What charger do you prefer" poll, I thought I'd throw this one out there as a poll to see where everyone stands on how often you hook your Reader up to charge.
I personally only charge when the thing shuts off on me, since I'm still skeptical about how often you can charge a battery w/o it developing some type of memory. I know, I know, I checked wikipedia and saw that Li-Ion batteries are reputed to not have the dreaded "memory-effect" that previous Ni-Cad batteries faced, but I'm still skeptical.
How long can I expect a Li-Ion battery to last while it's being used? Is there a specific MTBF

(mean time between failures) for this technology? If so, what can we expect and how do we replace our Reader batteries when they do fail?
Just a major concern of mine, fortunately for me in regards to my PDA, I have a spare that I can throw in w/o having to ship it off to $ony to replace. I'm sure it is just a matter of time before some enterprising company starts marketing a replacement battery w/ directions for a DIY, but until...