I share the following rule with younger developers and try to hold myself to it as well: If you look back at code you wrote 12 months ago and don't think, "Eww

I share the following rule with younger developers and try to hold myself to it as well: If you look back at code you wrote 12 months ago and don't think, "Ewww, what was I thinking here and why did I write it this way?", then you're not growing as an engineer. For very beginners, I change that to 4-6 months depending on how fast they're picking it up.