Most backyard projects don't fail during construction. They fail earlier — after the owner has already paid for drawings the lot can't support.
This community exists for the question that comes first: Does my lot allow a second unit — and would the rent or sale of that unit cover the cost to build it? If the answer to either is no, better to learn it here than from an architect's invoice.
ADU, SB 9, and SB 1123 are doors — pathways, not products. The product is a clear yes or no on your parcel, before you spend a dollar on design.
Each lesson leaves you with a named decision: one pathway, a stack of facts (or unknown), a kill list, a money direction, or a one-page brief. Unknown is allowed. Guessing is not.
City of Los Angeles examples appear often. Other California cities use different portals and overlays — do not carry one city's map to another.
Not legal advice. Not a loan quote. Not a permit. Confirm it on your APN. Every time.