Top 10 facts about the world. An accounting convention is a practice generally followed by all accountants as a result of custom, although changing norms in the accounting and financial industries result in periodic updates to them. Also known as accounting concepts, they are the groundwork of accounting.ne of the key accounting conventions is consistency. Once accountants adopt an accounting method they feel is appropriate to a client or setting, they continue to use it. This eliminates confusion and situations where accounting is unclear as a result of changing accounting methods.