A semi-hypothetical question.

Given that a First Class seat is worth 'something more', how much more
is it worth to you on:


a 5 hour flight?
10 hours?
15 hours?

Taking the above and normalizing by how many hours the flight is, do
you come up with a "$xx/hour" rule of thumb?


Basic reason for me asking the question is if to burn some miles and
dollars for an upgrade. It it were miles-only, it would be a no-
brainer, but the dollars adds roughly $25/hour.


-hh