Each case may vary, although most cases follow this course. A patentability search is not necessary. The reason for conducting a search is to determine whether the invention is patentable and if so what is the likely scope of protection. The principle counter consideration is the financial cost of the benefit. Often inventors perform their own search of the market and then of patents in a public library.
Legal counsel is brought in when quality becomes more important.
The inventor should be specific as to what they would like counsel to perform. The search can come with a formal written opinion or simply be copies of the prior art found in the search. Costs vary depending on what the inventor wishes to have the patent lawyer perform as does the work involved and the quality of the information received from the patent attorney. An inventor describes the invention to a patent professional, attorney or agent, and the professional drafts an application. This is typically done in the first meeting.