Within the customer profile page, you can click on the 'Insights' tab to view a quick reference to the client's sales-history within your business.
Here you can see a quick glimpse into your customer's average sale value vs your company-wide average sale value. You can see the client's total sale values broken-down by the service/product categories they have purchased.
Scrolling down, you can also see the revenue broken-down by the user(s) that created the customer's quote originally (often admin and sales staff). Lastly, you can hover your mouse over the revenue pie-chart to see the customer's total revenue in comparison with your total company revenue.