The important expectations
From client side : the value your company adds to the client
From your side : business continuity

The usual client engagement process is highlighted below
Request for proposal
Presentation meetings, post presentation followup or communication till you sign the deal
Client visits by team(s) from your company at client (multiple layers of contact within the office of the client)
Frequenct communication through Brochures, Physical /eMailers, Newsletters, Social Media (frequency depending on the person or role or department)
Customer Satisfaction Surveys
Annual Customer meets
Besides meeting the clients in their / your office, you tend to them in seminars / conferences / award ceremonies / exhibitions or social gettogethers ...

What companies should care
Client satisfaction surveys, and year on year performance.
The client satisfaction surveys should be done for multiple layers within the client office, specially if you are a service provider (e.g. IT), whose application is used by people in different organisation level and localities at client end.
Remember, sensitivites in people relationships are as important as product / service delivery..

Dont hide that small concern at client end, it may become the issue of discussion in business continuity.