Our Vostro runs on A/C 99.9% of the time. Should we periodically discharge the battery to maximize longevity? If so, at what threshold, and how often? Googling churns up tons of conflicting advice.
We've considered installing Dell Power Manager (DPM) and setting it at "Primarily A/C", but would prefer not to have yet another Dell app constantly running in the background. We're also not confident DPM would do a better job vs. a disciplined discharge schedule (or never discharging at all).
Never completely discharge the battery to power cutoff point,
Do not continuously charge the battery (set the system to charge the battery to about 70% and cut off charging),
Do use the system on battery normally once a month.
The other way to prolong the life is to remove the battery from the system and store it in a cool place. That's probably not practical, and since the battery will be in a hot system continuously, the above will be the best you can do to maximize the lifespan of the battery. Expect a couple of years out of it -- not more than that.
FYI, from what I've read and been told (by Dell Cares) the system will not continue to charge when it reaches any pre-set threshold (e.g., 70%, 100%). We'll do as you suggest and use our Vostro on battery at least monthly, run it down to ~ 50%, and recharge.