The recent fires in Southern California that devastated entire neighborhoods have put us all on notice that even those of us in suburbia need to pay attention to fire safety. The Woodside Fire Protection District has some excellent information on home hardening and defensible space (available here) that is very much worth reading. I will touch on a few key points below.
Immediately surrounding your home is the "Ember Resistant Zone" which extends 5 feet out from every structure. In an ideal world this is all hardscape; no combustibles like plants or wood chips allowed. Tree limbs that extend into this zone should be trimmed at least 10 feet away from the siding and roof. In addition, combustible furniture, doormats, etc. should be removed. It all makes a difference. The survival of Lahaina's "Miracle House" is largely attributed to its perimeter ember resistant zone and metal roof. If you haven't seen the pictures, google "Lahaina miracle house."
Extending from 5-30 feet out from your home is the "Lean, Clean and Green" zone. Here, irrigated plants are generally acceptable, but any dead or dying foliage or plants that don't get regular water should be removed. Also, the lower branches of trees should be removed (see document for guidance). Note that fences, sheds and play structures should also have a resistance perimeter.
The document also contains guidance for beyond 30 feet, I leave that for you to read.
If all of this feels a little overwhelming, maybe approach it in phases. If you have plants and trees in contact with your home, trim them back - which, by the way, will help extend the life of your roof and siding regardless! As you replace plants, be mindful of where they are being planted in relation to your home. That pretty bark or mulch? Relocate it or at the very least don't refresh it.
We had Woodside Fire inspect our home (for free!), and they recommended the removal of 2 medium oak trees overhanging our and our neighbors homes. San Mateo County (Ladera is unincorporated) didn't balk at the removal of the usually protected oak trees since they posed a substancial fire risk. Now, we do have a strip of irrigated citrus bushes near our front door that we were advised to keep below 3 feet tall. The concern here is that the trees could become a "fire ladder" enabling heat and flames to blow out the windows and reach the eave and roof above. Also on our to do list is to keep a couple of very large trees that overhang our roof trimmed to maintain the recommended 10 feet of separation.
Once again, the complete document is here.