The increasing uncertainties and risks associated with complex accounting estimates, such as fair-value measurements (FVMs) have made no clear-cut line between facts and assumptions. Thus, users perceive complex accounting estimates as less reliable, in comparison to other financial statements' items, which puts a strain on auditors to provide reasonable assurance regarding the appropriateness of these estimates. Additionally, the technological advances witnessed in the current internet era have led to the emergence of new digital assets such as cryptocurrencies. However, the lack of solid specific accounting and auditing standards concerned with the fair-valued cryptocurrencies' issues is putting an extra burden on auditors. Which in turn shows an increase in the nature, timing, extent of risk assessment and audit procedures, compelling auditors to exert additional audit effort. These incremental audit efforts and risks associated are reflected in the auditor's command of fee premium. Accordingly, this paper aims to identify the complex accounting estimates definition and characteristics, emphasizing on FVMs. Moving from this aspect towards the emergence of crypto-assets, such as bitcoins and other fair-valued cryptocurrencies induced by a distributed ledger relying on cryptographic blockchain technology and its effect on auditors' effort indicated by higher audit fees.