In message <https://marc.info/?l=openbsd-misc&m=161529766406753&w=1>, Jan Stary asks for research/references supporting the claim that a lithium-ion battery will last longer if it's not fully charged or discharged.
None of these qualify as original research, but some sources for this guideline include https://www.wired.com/story/smartphone-battery-care-last-longer/ https://www.apple.com/batteries/maximizing-performance/ Table 4 and Figure 6 in https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries The last of these is the most technical, and does cite some original research.
