You need to segment your customers based on how recently you have closed won business with an existing customer. For example, a report showing those customers that you have not had a recent closed won opportunity within the last 4 years and customers that have had a recently closed won opportunity within the last 4 years. Salesforce does not allow you to easily find this information.
1) Create a date field on the Account object that will store a value calculated by Rollup Helper for the first closed won opportunity in the last 4 years.
2) Create a MIN rollup to grab the first closed won opportunities close date and roll it up to the Account Object.
3) Create a new filter where Won = True and where the close date is greater than the last 4 calendar/fiscal years.
4) Create a schedule to run every year to make sure as a new year comes and goes, that the roll ups are recalculated.