I’ve often heard the rule: “Never use 90° traces.”

But I’m curious how much this actually matters in real-world PCB designs.

My current understanding is that, for many low-speed signals, a single 90° corner is unlikely to cause a noticeable problem. The corner does slightly change the local trace geometry and may introduce a small impedance discontinuity, but whether that matters seems to depend on things like:

Signal rise/fall time
Trace width and stackup
Controlled impedance requirements
The rest of the signal path

For faster signals, RF layouts, or tightly controlled impedance traces, I can understand being more careful. But for ordinary routing, is avoiding 90° corners mostly just good convention rather than a strict technical requirement?

I still tend to use 45° bends, but I’m interested in how experienced designers approach this in practice.

Do you avoid 90° corners in every design, or only when the signal requirements justify it? Am I missing any important considerations?

How Bad Are 90° PCB Trace Corners in Practice?