Sparky - you are in CA - CA Contractos State License Board is at
www.cslb.ca.gov - this site has EVERYTHING you need to know about CA contractor requirements - I'll expand on your question just a little bit. 1. You must be a licensed contractor if you do more than $500 in work (this $500 includes materials/fixtures). 2. If you do work in a residence you MUST also be a certified (through the state contractor board) Home Improvement Contractor (HIC). 3. Almost any work done requires a permit (to answer your original question). Check with the local jurisdiction but technically you need a permit to replace a defective light switch. I just worked on a home that was completely rennovated - new roof, new stucco, new water heater, new kitchen, gas and water lines moved, all new windows/doors throughout, carpet, paint....I was the ONLY licensed contractor on the job! Really pissed me off, but I did tell tell the other tradesmen that if I even found one of their fingerprints on any of my electrical work I'd be calling in the state contractor board.