I usually can find out the issue from the routine work. For example, in May 2016, our team was responsible for an Interim annual audit. Our project manager used a normal method to define the account receivable and bad account loss, but when I check the companies historical data, I suddenly found out that the method was definitely unfit this company. I took one more day to use a different rule to reconfirm the account, and after discussion with my manager, it turned out that it is a critical finding.