Traveling and Workamping in Calif.... DMV info...

I am always a little surprised, and a little annoyed, when I hear someone complain that California expects them to pay taxes (DMV, etc.) if they live here more than 6 months per year. No doubt that cost of living in CA is high, and full-time RV people are often on fixed incomes. But is it fair for the people who live, work, and pay taxes in CA to cover your costs too? Seriously, if you are here more than half the year, should you not pay your share?