Yes, society generally deems it rude, but I don't :-)

I'd managed to save about £40,000 GBP by the end of 2012. Then in 2014 I took some months off from Readlang and earned roughly £30,000 GBP doing some contract work. No other sources of income. I've never been close to running out of money, if I did I would certainly ease back on Readlang and look for more freelance work.

BTW: The freelance work I did wasn't using technology I enjoy or want to focus on in future, and was offered to me without having to look for it. I did it because of the money and because I liked the people. I've never actually had to actively look for freelance gigs myself. So I'm still not sure how easy it is to find good clients with interesting work.