In its development and evolution every company faces non-standard tasks: M&A, restructuring (either operational or tax/legal driven), global expansion and so on.
Such cases require specific knowledge and commitment, which typically means dedicated professional who can have helicopter view on the situation and help C-level to solve the challenge.
Probability to find such specialist quickly to onboard in-house is very low... Also questioning further responsibilities and tasks of such expert when the project is finished.
My 15 years experience in both Big4 consulting and in-house roles inspired me to open my boutique. My philosophy is to come when business requires me to success in one-off non-standard process.