Agreed, but not necessary in reference to any battery memory. Lipos don't function like nicads of other lead acid batteries. They really don't form a memory. Important (main concern) with lipos is after storage it's a good idea to charge them more so for the balancing of cells. Storage is good 40-80% doesn't really matter just not a full charge. Reason for that is temp based. If you have a 100% charge at 60 degrees and store them, then say they warm to 80 degrees (from surrounding factors not battery) the internal chemistry may produce more voltage resulting in a over charged battery, and that is bad. Some people put them in fridge but totally not necessary, actually introduces moisture that can lead to terminal corrosion. Minor issue. On almost all "smart" chargers the last 10-5% is not really charging but balancing cells. That's why it usually charges up to 90% pretty fast and that last little bit may take longer as its into a balance cycle.
I would full charge them after storage, only if you plan to use them within the next couple days. Storage - just a cool dry place, but as with any battery the potential is there so some common sense like not next to the weed eater fuel can
. If you ever have to get rid of one from damage or bad cell, a bucket of saltwater overnight will kill them. I had to say good by to a couple and gave them the burial at sea!!! Don't think it's necessary but I stick a wire into ground from bucket just to help. Then they will be inert and can be tossed in trash (unless lithium is a hazmat).