I preach and teach a lot of principles from the Jewish roots of Christianity and I always tell people that they can keep any of the "laws" they wish, if they feel the need to, but don't require that of others. Too many make their conviction a requirement for everyone. The principle of the Sabbath is a good one! People keep it with varying degrees.
I asked a Rabbi once, as I sat in his class, about the Rabbi working as a Rabbi on the Sabbath. He looked at me with a "only a Gentile would ask a question like that" look and said that the Rabbi could take another day as the Sabbath.