if you plan a system with "three days of autonomy", it is pretty hard to to run the ESS from 0-100 % "daily" .
I have no issue using the 'whole' capacity of the packs, and don't care about "warranty" - most of my packs are DIY, and I doubt the factory packs warranty is worth a Dime.
What is "daily" use - depends a lot on weather and loads being used.
In summer it can be normal to run 70 % - 100% most days, and drop down to 30%-70% during a week of poor weather.
In winter it can be normal to run 30%-60% daily, and top up a bit from chargeverter at night to make up from short-fall of solar that day.
I set my low cut off at 10% - just to have something left if needed - but have only seen once that the system ever hit that low value - gotta keep an eye on the Official Solar Tester sometimes.