Ask a few key question
To make the customer aware of age of the current lighting and thereby opening them up to consider an upgrade (now).
Since older installations are often less energy efficient, application bundle is a solution which brings up to 65% energy savings.
If it was never checked (or checked a long ago) there is a chance it does not (or no longer) meet the minimum requirements according to standards.
If the values are not meeting the minimum, this can affect the safety and comfort (productivity) of the people working in the facility.
To establish if the sensors would make a difference.
If people work flexible hours, coming and leaving at different times, or if they accidentally leave the lights on - indeed sensors can contribute to energy saving/costs.
Step 4: Picture your customer