I actually think it is becoming more common.
I WAH 100% and DH also has flexibility to do telecommuting. We have the $ to do it. I know many people in the same situation that work in different locales throughout the year (or at least when kids aren't in school).
I am looking into places to go for 2 months in the summer that are cooler than DC and have the beach. I can work remotely. I would hire help for the kids and/or enroll them in camps. Grandparents would also be willing to come out for weeks at a time if I pick somewhere nice

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We do have in investment property in NW. If we sold it we could buy something else--but the rowhouse is such a great $ generator and year-round, hassle-free rental unit that it doesn't make sense to sell it.