The definition of a reversing entry is a journal entry that is intentionally made at the beginning of the next accounting period which is the exact opposite of the adjusting entry made in the previous period. This entry is used to offset the previous adjusting entry that was made to avoid the double counting of revenues or expenses or if expenses must be allocated between two periods. This type of entry is used with accrual based adjusting entries. The pros are that it keeps accounts from being overstated and the cons are that it can be used to cover poor accounting practices. Reversing entries are optional because they are used to simplify bookkeeping procedures.