What do I need when I buy a used car?

As a general rule you should always have the car checked out by a mechanic if you don't know what your looking at, in CA its buyer beware, as in sold as is, and yes a smog check within the 90 day limit is a good selling point but unless otherwise stated not necessary for the sale of the car, back to buyer beware. once the title is signed over and the release of liability is filed its your baby and your problem, but other than that its just a trip to the DMV with the title and bill of sale pay the fees and wait for the new title in the mail. they will give you the new tags and registration on the spot as long as its smogged and you show proof of insurance.