In general, many clients are new to the search engine optimization process. They have been exposed to the search engine optimization process during the sales cycle; however to get started off on the right foot, it is good practice to run through the procedures of the search engine optimization process again at the start of the seo project.
Reminding your client of the procedures that you will be employing during the project keeps their eye on the ball, educates them about why/what you are doing, and paves the way for better understanding and acceptance of your seo practices as you work through your process. When your client understands what you are doing, why you are doing it, and by continually providing measurements of success along the way usually leads to a better working relationship during the course of your project.
Simply marching down the road without an informed client generally leads to client confusion and frustration, as well as time consuming questions to be answered that, if your client had been more informed in the beginning, may not have been needed to be asked. Keep your client informed and educated as you work your project and you will be able to apply and implement your seo practices without having your back to the wall.
Save the worry for when a search engine changes its algorithm. If you have educated, informed, and communicated with your client over the course of your project they will better understand what changes to an algorithm means. Ultimately, they will have built trust with you which is incredibly important to a lasting relationship.
So I hope this simple reminder of setting proper expections with your client helps you get started on the right foot.