When you use an item for the first time, you must include the cost.
Items that are not used
You do not have to report spending on items that are not used (for example if leaflets are never distributed) and this does not count against the spending limit.
You should retain the unused material or evidence it was destroyed.
If you use the leftover items at a later election, you must report the spending on those items at that later election.
Re-use of items
Where you have paid for an item, you must report the full cost at the time of first use, even if you intend to use it again at a future election.
If you do use it again at a subsequent election, you do not have to report the original payment again. There may be some associated costs which must be reported at that election, for example for storage or cleaning.