Novelty is the most important thing. If you have a possible patentable invention, your patent attorney is the first person who should know about this! (S)he is the expert in the first place to check for you whether your idea is novel on first sight and is then able to draft a patent application and to file it. The first date of filing is important; from that date your invention is (provisionally) protected and in case the patent application is continued within one year in another country the first date of filing remains valid as the date your idea has been recorded. Furthermore the patent attorney represents the inventor during prosecution before the patent office and handles the payments, for instance for the renewals of the patent rights. Of course, as the client, you will always be consulted.