Nothing is enough or too much. As I use miles more, I try every trick to accumulate ever faster. Each time I think I will not be able to use them in time, but as I learn how to get more, I seem to be learning how to burn more each year! I am comfortable with high balances in more programs as I understand the value of the miles more and more.
And with Award Wallet helping me count, the answer to the OP's question is "my own". I can not see anyone else's anyway and I am getting more and more and spending more and more.