I like to invert that to: do I produce code I am perfectly happy with in regards to readability and maintainability or would I benefit from another pair of eyes?
Every question I get (when my code is reviewed) is a signal that code could be more self-explanatory, unless it is a complex algorithm itself, and that my — by now deep — exposure to the problem is keeping me misguided about what is and isn't "obvious" or "clear". A reviewer can take a step back and help ensure both them and I will be able to easily grasp the same code 3 or 24 months later.
Note that one of the best advice I got early in my career about doing a good code review is that you "just" need to ask good questions: the point is not for a reviewer to show how much smarter they are, but for both to develop a shared understanding and ensure code can be interpreted as quickly as possible.
Does everybody produce completely readable, tested code every time? Perhaps that's just "style" to you when it is "maintainability" to me?