Having been in the perhaps bad habit of keeping the power cord in once the battery was charged and seeing how after a year the 'health' deteriorated, I saw the light and fully charge and discharge the battery and have lost negligible 'health' after 400 cycles. It is my understanding that whilst it's possible to run a laptop as a quasi-desktop without battery and just power cord (albeit a bit sluggish on my steed) the fact that the battery is very slowly discharging and then gets a strong 'bump' of charging power when reinserted, it is frowned upon. Some say whole cycles are best, others part cycles, who knows…
SHJ