There is no more fatal blunderer than he who consumes the greater part of his life getting his living.

Earning takes up most of a life for most people, and that is a fact about how the world is arranged rather than a personal error. The warning is aimed at the version where it expands past necessity: more hours than the money requires, taken on out of habit, status or fear of stopping. That part can be examined.

So ask what the extra hours are actually buying, and whether you decided on them or drifted into them. If they are not negotiable at present, protect what is left rather than judging the total. What matters is whether anything remains for the life the earning was meant to fund.