Under California Code, Business and Professions Code – § 17910, Every person who regularly transacts business in this state for profit under a fictitious business (“FBN”) name shall do all of the following:

(A) File a fictitious business name statement in accordance with this chapter not later than 40 days from the    time the registrant commences to transact such business.

(B) File a new statement after any change in the facts, in accordance with subdivision (b) of Section 17920.

(C) File a new statement when refiling a fictitious business name statement.

Per LA County, a fictitious business name statement expires every five years from the date filed with the County Clerk.

Per LA County, if you decide to continue doing business under your FBN, it must be renewed every five years from the date filed with the county clerk to avoid expiration.

Pursuant to Senate Bill 1467, a Notarized Affidavit of Identity form must accompany all Fictitious Business Name Statements (Original, Refile, and New) 
If the registrant is a corporation, a limited liability company, a limited partnership, or a limited liability partnership, the County Clerk will require a print-out issued by the California Secretary of State indicating the current existence and good standing of that business entity, no other state evidence will be accepted.
Filed copy of the statement must be published once per week for four consecutive weeks in an adjudicated newspaper in Los Angeles County.
Publication must begin within 30 days after a fictitious business name statement has been filed, pursuant to Business & Professions Code 17917(a)