Dates can be added/amended/deleted as required.
The system will dynamically refer to these dates as required.
It is therefore easy to change period or year end dates.
Simply edit/delete entries.
Transactions can only be entered for "open" periods.
If required, period dates can be switched on/off as necessary to ensure transactions are checked to have valid dates.

The period shown above are manual, but can be monthly or for any period of time.