It's easy to forget that you're an expert.
Even if you're a junior.
You look at the problems you've got to solve.
You spend so much of your time searching for answers.
You feel like you don't deserve to charge for the stuff you do.
But you're still an expert.
You know more than your client.
You are fixing their problems.
You can do stuff that most people can't even begin to imagine.
I've been a Ruby developer for 15 years - and I still have to google how to generate a CSV every couple of weeks.
It doesn't matter if you don't remember it all.
It only matters that you make a difference.