How do software engineers actually know they're ready for the next career level?

I've been thinking about this problem while building JobTarakki.

Software engineers have plenty of signals about their careers — years of experience, job title, projects, technologies, promotions, compensation, etc.

But there's still a difficult question:

"Am I actually ready for the next level?"

A Senior Engineer might have 7 years of experience but still not be operating at Staff level. Another engineer with 5 years might already be doing Staff-level work.

So I'm curious:

What signals do you personally use to decide whether you're ready for your next career level?

Is it:

• Technical depth?

• System design?

• Scope of ownership?

• Business impact?

• Mentoring?

• Cross-team influence?

• Something else?

I'm building JobTarakki around this problem and would genuinely love to hear how other people think about it.