I specialize in the Los Angeles Condo Market (and focus on West Hollywood Condos).
My experience has undoubtedly confirmed that both Buyers and Sellers of condos are best served when using a Realtor.
It is the responsibility of both the Listing and Selling Agent to know as much information as possible about the Condo Building and the Homeowner's Association (HOA) to which all owners belong. Specifically, the Realtor needs to be familiar with the CC&R's and Rules & Regulations governing that HOA.
Obviously it is the ultimate responsibility of a prospective buyer to familiarize himself/herself with the details contained in these documents, but at least the agents should know some of the more onerous requirements on owners.
A good example is the "Move-In/Move-Out" guidelines: Is there a "move-in/move out" deposit? How much is it and when is it payable? And are there specific procedures that the owners need to follow when moving?
There are often penalties and fines for non-compliance of the Rules and Regulations which could be avoided if the agents involved are familiar with the HOA governing documents.