For example, you find a crate that seems to do what you need. 1) are you sure it has high enough quality? 2) Is the license compatible with your needs? 3) What long term guarantees exist for API stability? 4). Is it actually maintained?
All of this needs checking off. If you don't do them, your project will be a sprinter, not a marathon runner, as dependency addition is cheap but dependency maintenance is a slow burning major cost.
The transitive dependencies make it worse, as they need independent vetting.
This cost is acceptable for major libs, but the zillion 100-line left pad ish libs have to go.
I'd love to have some standard rust guarantee declaration, including at least the declaration of the author's intent. You won't maintain something or won't stabilize an API? Fine, your project, your rules. But don't make me hunt for that info.