I think it's relatively easy if you work within companies of a certain size. If so, compare yourself to another 100 developers that you've worked with. If you only work with start-ups, it may be more difficult.
Questions to ask yourself:
- Do you consistently get higher ratings than your peers?
- Do other developers come to you first if they want advice on the correct way to do something?
- Have you produced features that cause applause in sales teams or customers?
- Have all of your products been successful (maybe allowing for slips in schedule or budget)?
- Do people understand your code? (i.e. do you get a lot of emails from people asking to explain things?)
- Do features that you have created have significantly fewer bugs than other features?
- Do tech leads or product managers seek you out to help them build products or features?
Questions to ask yourself:
- Do you consistently get higher ratings than your peers?
- Do other developers come to you first if they want advice on the correct way to do something?
- Have you produced features that cause applause in sales teams or customers?
- Have all of your products been successful (maybe allowing for slips in schedule or budget)?
- Do people understand your code? (i.e. do you get a lot of emails from people asking to explain things?)
- Do features that you have created have significantly fewer bugs than other features?
- Do tech leads or product managers seek you out to help them build products or features?