I would not worry about that too much. You paid for the cells....use them based on what you need and don't stress over it. You already know a cell that's fully cycled each day in ideal temps will last for at least 5 years. I think keeping the cells between 3.0 and 3.4 volts is the norm for extending cycle life. We need more data concerning this.What maximum discharge levels are recommended for being ‘gentle’ and extending cycle-life?
A cell discharged to 2.5 volts will bounce back to higher voltages fairly quickly.I’ve been discharging my 8S pack to 25.3V (or ~3.16V on my well-bottom-balanced pack) at a discharge rate of ~20A or less than 0.04C and the voltage pretty quickly snaps back to 25.65V or just over 3.2V per cell soon after low voltage disconnect…
I think EVE recommends replacing the cell when the capacity drops to around 70%. Some manufacturers recommend replacing them at 80%. I wonder if this is because they are concerned about possible internal shorting if going beyond that?