I’m no expert, but if I recall correctly, lithium-ion battery life is tied to the number of charging cycles, not how deep the battery is discharged. Bottom line, to maximize life you should run plugged in as much as possible and only run off the battery when you really need to.
Again...I think this is correct, but I could be wrong.
I basically ran my original battery like this: 2. New battery pack needs to be fully charged and discharged (cycled) a few times before it can condition to full capacity.
So basically every time I used my laptop I was cycling the batteries.