"Time I'm willing to dedicate to your interview problems" and "time I'm willing to dedicate to reading and writing on HN" are not freely interchangeable; you can (and presumably do) have radically different expectations of the costs and benefits that make them incomparable.
"Time I'm willing to dedicate to your interview problems" and "time I'm willing to dedicate to reading and writing on HN" are not freely interchangeable; you can (and presumably do) have radically different expectations of the costs and benefits that make them incomparable.