How do you decide if a repetitive task is actually worth automating?

I fell into a trap where I tried to optimize every minor step in my daily routine. I’d waste a whole afternoon building a complex setup for a task that only takes five minutes a month.

I realized that a basic manual process you understand instantly is way better than a complicated setup you constantly have to fix and maintain. Now I only automate things that waste significant time every day.

What rule or filter do you use before buying a new tool or building a new workflow shortcut?