Re: How important is it to generate private keys from Ledger wallets?
Is this really correct?
Anyone is free to double check my math. 
A trillion Earths with a trillion people each with a trillion computers each generating a trillion keys each per second. That's (1012)4. 13.7 billion years since the birth of the universe, multiplied by days, hours, minutes, seconds. 4.3*1065 keys generated since the dawn of time.
There are 2256 private keys (in reality slightly less, but for the purposes of this calculation the difference is so small as to be irrelevant).
(4.3*1065)/(2256) = 3.7*10-12 = 0.0000000000037 as a fraction, or (round and multiply by 100) = 0.0000000004%.
However, if you have a family it is important to allow a familiar member know how to retrieve them as well, especially if you have kids.
Good point, and I should have been more specific when I used the phrasing "you are the only person". Obviously, if you are the only person who knows how to access your private keys or where your seed is backed up, and something happens to you, those coins are lost, potentially forever. If you want your family or friends to inherit your coins, then you need some sort of recovery system - anything from your partner also knowing where the seed is backed up, to an elaborate 3-of-5 split secret or timelocked transaction.