Doing DIY legal for your business is like doing DIY earthquake prevention for your business. Chances are, if your business is going to fail, it'll probably fail because you're out of money, time, customers, employees, etc., not because of legal troubles or earthquakes... furthermore, there are tons of small businesses who are of a dubious legal / earthquake preparation, but nevertheless make money and do fine for a really long time. But when a major earthquake or lawsuit does occur, you're probably going to lose everything without proper earthquake / legal protection (you might still lose everything with proper earthquake / legal protection).

So should you do your own legal? Yes if you're <20 employees, no if you're >40 employees or you're putting your business through a hype-generator and you've generated hype or you think the law profession is somehow worshipful and you're cowed by lawyers.

I like the earthquake analogy.

Also, most legal screwups won't cause a company to fail—but they will cause unnecessary expense, distraction, and stress. The point is that all of that's preventable if you are careful.

I formed my LLC for consulting with LegalZoom. Of course a different company might require representation. I'd surmise that if you don't know the difference, and you just go the attorney route out of default, you probably don't have a deep enough understanding of your company for long-term success.

There's also the issue of illusions of grandeur: spending big dollars in legal fees is its own form of cargo culting.