When I started w*rking many years ago, the stated rule of thumb was 10% of your income. So, inflation rules here as well.
The rule also assumes w*rking longer than anyone here wants to do.
Seriously, I think that that amount is ok as a general rule for the average person as a
starting point to think about saving for the future, and most here far exceed this minimum. Further, without a clear understanding of your spending and investment mix in relation to earnings, it doesn't give you much guidance or assistance in real planning and goal setting.