Why you don't have confidence even though you have 10 years experience
The 10 year rule says you should be an expert by now!
You’ve been in the industry or maybe even just writing code for 10 years. Have you ever heard someone tell you “It takes 10,000 hours to become an expert in a skill”? 10,000 hours or the “10 year rule” are both measures of time, but they only speak to one aspect of mastering a skill. Ask yourself, over that period of time did you push yourself or did you fluke it? Did you make sure you were learning and growing at every opportunity? Or did you ride the wave and feel a sense of just scraping by at every stop?
The passing of time doesn’t automatically grant you the maximum amount of knowledge and skill gained during that time, however as time goes by you start to expect things from yourself as if it should.
Why is that? I think the reason is all about comparison. You compare yourself to others with the skill and you wonder why you are not at that level yourself. Maybe others obtain recognition of their skills years before you so rather than thinking about the work involved or the reason behind it you just assume you should be there too.
Being honest with yourself
So did you push yourself and really try all those 10 years? It’s a hard question to be honest about to yourself. You don’t want to feel like those years were wasted do you? But it’s important to come clean with yourself. If you’ve just been telling yourself you did what you could, but you don’t truly believe that, nothing is going to change.
You have to really be honest with yourself. Acceptance and forgiveness are your friends. Confidence comes from truth and a belief in yourself. You will never believe the lies you tell yourself knowing they are lies.
It’s not a loss
The realization that you can be better should be freeing. If you didn’t try yesterday and you’re doing ok, imagine what you can achieve by trying today. Prove to yourself what you can do and you will inherently become confident.
Something I read a while back that really stuck with me:

The 11th Year
This year you have to think to yourself at every opportunity, do I really believe I have pushed myself to grow. If you ask it only once at the end of the year you have failed yourself. It needs to be asked daily. Review your growth every week and validate it. Prove your ability to yourself at every chance and you will realize confidence at the end of the year.
That is my new years resolution. What is yours?
— A D