Basically, you should aim to minimise complexity in software design, but importantly, complexity is defined as "how difficult is it to make changes to it". "How difficult" is largely determined by the amount of cognitive load necessary to understand it.
Ultimately, context, industries and teams vary so greatly that it doesn't make sense to quantify it.
What I've settled on instead is aiming for a balance between "mess" and "beauty" in my design. The hardest thing for me personally to grasp was that businesses are indeterministic whereas software is not, thus requirements always shifts and fitting this into the rigidity of computer systems is _difficult_.
These days, I only attempt to refactor when I start to feel the pain when I'm about to change the code.. and even then, I perform the bare minimum to clean up the code. Eventually multiple refactoring shapes a new pattern which can be pulled into an abstraction.
Also, people confuse familiar with simple, they tend to find things simple if they are familiar, even if they are complex (interwine a lot of different things).