If you want something done right, write a procedure for it. Businesses are complex beasts and over time, if everything you do and how you do it only exists in your head, you’re never going to be able to hire anyone to help you scale the business.
Even worse – what if you’re not able to work? Or you need to cover someone’s sick or maternity leave?
If the only person who understands how to do the job is out for a month you’re left unable to complete those tasks correctly.