Opportunity cost (time not working) is often more expensive than flight and lodging.

Surely everyone gets some paid vacation time.

> Surely everyone gets some paid vacation time.

Not in the US.

https://www.bls.gov/opub/ted/2017/mobile/73-percent-of-all-c...

Also technically receiving paid vacation and actually being able to use it are often not the same: in retail us at the bottom of ten end up cashing out vacation at the rate of a few hours a week to compensate for getting fewer hours a week in the slow season but still have enough days scheduled (or are functionally on call) that we can't leave town.

I work for myself. Even sleep has an opportunity cost.

Marginal utility of time spent working usually declines.

That is to say that time off will pay off in increased productivity.

Another way to say it, insufficient rest has its own cost.

15 days per year, and that's quite lot compared to most previous jobs I've had.

What are you doing the work for?

For fun? Strange question. Almost as if you were asking rhetorically.

No, that's an answer. I also mistook you for the parent comment.

To each their own but seeing travel, or even a short non-work break of some sort, in purely economic value might not be the most healthy outlook.

Who knows -- if you were to take even a one week trip somewhere else maybe the time away from your work will give you better insight into it, or even better thoughts/ideas, that might lead to more money / economic power, if that's your goal.

One can consider opportunity cost without forgetting non-economic value. I take more vacation than most Americans, probably more than most Europeans, too.