I also think it can be job-specific. For example, I'm working on a website on the side which requires both more administrative work and more product/creative wo

I also think it can be job-specific. For example, I'm working on a website on the side which requires both more administrative work and more product/creative work than my day job. My day job is in marketing, and the more time I take off the more time I'm not running performance marketing campaigns that generate revenue every day. I think vacation is very specific to job function in many cases -- in one I would definitely reach burn out and in another I wouldn't. In creative work, like if you're a graphic designer, I can imagine not taking a break would have greater repercussions on the creative process than in my job.