Some Generally Accepted Accounting Principles (GAAPs) are complementary and some are conflicting in nature.
Comparability and consistency is complementary. However, completeness and materiality is conflicting in nature. Similarly, prudence and matching principle is conflicting in nature. Matching principle states that expenditure that are made to earn revenue should be recognized in same accounting period.
Accounting period is different from calendar and fiscal year end. Accounting period can be less or more than 12 months and can be started at any month.
Prudence principle states are expenditure/liability should be recognized immediately as anticipated or probable such as provisions and revenue/asset should not be recognized until earned such as account receivable.
In practice, balance needs to be achieved, which require the ability to exercise judgment by professional accountant. Professional accountant knowledge, skills, experience & ethical view point influences his/her judgment.