Does a messy add-back list make buyers suspicious of my whole valuation?

Yes, often more than the individual items warrant. Add-backs — expenses run through the business that a buyer wouldn't need to continue, like a personal vehicle, family member salaries, or one-time costs — are a normal and legitimate part of presenting a business's true earning power. But when the list is disorganized, poorly explained, or padded with items that are hard to justify, buyers and their advisors tend to lose confidence not just in that list, but in the financial statements underneath it.

The nuance is that a credible, well-documented add-back list actually helps you, while a messy one hurts you more than having fewer add-backs would. Each item should be clearly explained, ideally with some supporting documentation, and genuinely something the business wouldn't need to continue spending on under new ownership — a personal expense is a much stronger add-back than something that's arguably still a real cost of running the business.

Cleaning up this list with your accountant before you present it to any buyer, rather than assembling it reactively once due diligence starts asking questions, is one of the more straightforward ways to protect the credibility of your whole set of numbers.