10-15 vacation days in the USA is typical, especially with less than a decade of experience [0][1]. I do wish I had more vacation (I get 15 days), but if I use it all each year and avoid working nights and weekends, I never feel symptoms of burnout. If I add my hobby projects, 60 hours a week feels sustainable, especially if I watch for feelings that might lead to burnout and take immediate corrective action.

Even worse: sometimes your responsibilities increase faster than your vacation days. My Dad was unable to take half of his vacation at his old job because of the amount of the company he managed.

[0] http://www.infoplease.com/ipa/A0922052.html#axzz0x9O67WhF

[1] http://media.expedia.com/media/content/expus/graphics/promos...