It comes down to the marginal utility of your money vs. the upgrade. For example, I fly Singapore to Tokyo about once or twice a year, sometimes more often, al

It comes down to the marginal utility of your money vs. the upgrade. For example, I fly Singapore to Tokyo about once or twice a year, sometimes more often, always on Scoot, a budget airline run by Singapore Airlines. Upgrading from economy to ScootBiz costs as little as $80 with their "bid for biz" program. I always "bid for biz" and it's absolutely worth it: early boarding, free food, much more space (for yourself and your carry on), etc. So the marginal utility of the upgrade for me is worth more than $80. At some level of net worth, flying First on a legacy airline to Tokyo, maybe Japan Airlines which I had to take in economy once for $1,500 vs the $200 or so Scoot can go down to, would have more utility to me than the $10,000 extra I'd have to fork out. I don't know what that net worth would be (probably north of 50 million), but I know that past perhaps a few million dollars in liquid assets, I would always fly business even at 3x the cost, and I know plenty of people in that situation doing exactly that. And there's people for whom flying SQ Suites [1] for $30,000 one way is a "discount" from flying the same route privately. [1] reposting because such a fun read: http://dereklow.co/what-its-like-to-fly-the-23000-singapore-airlines-suites-class/ http://dereklow.co/what-its-like-to-fly-the-23000-singapore-...