I don't pretend to be perfect, but I don't make many mistakes--at least not when it comes to financial reporting. I recognize that such mistakes are costly, and never acceptable. If I'm not 110% sure about a calculation, assumption, or financial record, I consult with a colleague or other experienced accountant. I seek confirmation of alls results through IAS and IFRS. I always double check my work, and if it's really important, I'll have someone else check it too.