Some filters change with the day or the user. Tokens let a saved view stay correct without editing it.
In a date filter: %today, %workdate, %yesterday, %tomorrow, %week, %month, %quarter, %year (each resolves to the current period) and relative ranges like %workdate-7d..%workdate. In a user filter: %me (your user ID) and %user. In customer, vendor and item filters: %mycustomers, %myvendors, %myitems, which use the lists on your role centre.
Save a view with Due Date ..%today and Salesperson %me and you have "my overdue" that is right every morning without touching it. Tokens also work in report request page filters, which is what makes a scheduled report useful (tip 36).
