Every battery will degrade, and every battery will degrade at a different rate.
Really, only Tesla can tell if the battery has degradation outside of the normal range.
I believe they already have on paper, that if it degrades more than 30% while under warranty, you get a replacement.
I suspect the reason they have it at 30%, is because if you abuse your battery, it can degrade quicker than others. The warranty protects us, but also Tesla against this abuse.
NO ONE here with significant battery degradation is going to say, “my battery has degraded more than most, because I abuse it”.
(Not suggesting that you did though either).
A modem combustion engine can last many decades, or 12 months, depending on how you treat it, or abuse it.
There are many things you can do to dramatically shorten the life of a combustion engine.
The same applies to our batteries.
-Charging to 100% too often, can quicken degradation.
-Charging to 100% and letting it sit there too many times, can quicken degradation.
-Using Superchargers too often, can quicken degradation. (As per popular belief)
-A lot of fast discharging, (eg. Too many 0-60 runs), (Have been rumored to quicken degradation).
If you do all of these or most of these, you will quicken degradation even more.
It’s still good to read about who is experiencing degradation, so we get a flavour of what’s going on, but only Tesla can determine if the degradation is self imposed or premature, based on data from the car.
Like I said, no one here is going to say, “I have excessive degradation, and it’s due to battery abuse as per above.”
There is only one person on this forum, that admitted to doing several things in the list above that will quicken degradation. Can’t recall his name, but he is leading the car, and doesn’t care, so he just admitted to it.
No one else will though. ..