the quickest way to lose battery capacity is to do deep or full discharges.
running the battery all the way down will cause it to not last as long.
I think this is misinformation, and should be discounted unless you provide a link to a credible source. Lithium batteries can be damaged by overcharging or over-discharging (but they are usually well-protected against that), but nothing I've ever seen from a credible source claims that doing full cycles reduces the capacity or lifetime relative to smaller swings.
