Whether they know it or not, financial statement preparers are entering a period of accounting change like no other in recent times. An SEC filer with a calendar year-end will have to account for revenue using a fundamentally different model on January 1, 2018, recognize right-of-use assets and lease liabilities for most leased assets on January 1, 2019, and apply a profoundly different model to measure credit impairment on certain financial assets measured at amortized cost on January 1, 2020.