What is the best way to handle delta sync for calendar long term synchronization on Graph API

Question

We plan to synchronize the resource calendar using the "calendarView delta" method (https://docs.microsoft.com/en-us/graph/api/event-delta?view=graph-rest-1.0&tabs=http).

We have found that it is possible to synchronize a calendar without specifying a start and end date, but for now this feature is in beta.

What is the best way to retrieve the events of a future period, while time is running? For example, if we want to retrieve the events of the coming year, we need to create a delta [today, year +1], but next month this delta, encrypted in the token, will represent the period [month -1, month + 11] .

We thought of a solution that would consist in renewing the token every month, but this has two drawbacks: it forces us to run a full synchronization once a month for all synchronized resources, and we don't really synchronize a sliding one-year window.