If it's just you (you're a solo founder) and you don't have the money or see the value yet in establishing a relationship with an attorney that can give you real advice (more than just filling in form documents), LegalZoom and Clerky (my preference) are great for forming a company. Simple and inexpensive.
They are also great for certain contracts that are little more than fill-in-the-blanks in most contexts, e.g., a non-disclosure agreement. They may be fine for trademark applications, as well, if the mark is very unique.
Have I seen founders mess certain things up by going the DIY route? Yes. Is that likely? Not in these contexts, IMO. And, BTW, I have seen lawyers mess these things up, too. So, don't give in to fear mongering when it comes to making a decision here.
Where the DIY services don't get the job done is with true founder agreements (e.g., an LLC Operating Agreement, a Shareholders Agreement). The only way to properly get that job done is with a lot of discussion and, almost always, custom contract drafting. You can use off-the-shelf solutions here, although, having done this many, many times with founders, they usually don't want the off-the-shelf solution when we actually talk through what those documents say. We may modify the buy-sell provisions, the vesting schedules (the standard Silicon Valley vesting schedules that you will see in the market often don't work for founders -- they make it extremely tough to part ways with a dead weight founder) or the way you make decisions as a team. It's very rare I cut and paste documents like this and, in case it isn't abundantly clear, LegalZoom is basically a cut and paste exercise. The contract template systems have limited Q&A and aren't built for anything that doesn't neatly fit into a certain box. Again, they can absolutely work for Certificates of Formation/Articles of Incorporation and NDAs -- very simple documents.
The same goes for form customer contracts -- those usually require custom drafting that LegalZoom isn't built to provide. Of course, you can use an off-the-shelf template for these documents, as well, and if your budget doesn't allow for a real attorney, it's almost certainly better than nothing.
At some point, you want to invest a few dollars in a strong business attorney who can create documents that are custom for your company and your cofounders in the contexts where it matters most. And, you ought to ultimately find value in your attorney as someone who can talk intelligently with about other documents you might consider (or that you can do without), legal risks generally and navigating all the legal and business issues that are in front of you, including raising capital and scaling an operation. They ought to be willing to tell you when you need them and when you don't.