Do you have 20 years experience or do you have the same 1 year of experience twenty times? ~Scott Hanselman
Just like running, or weight lifting, or anything you have to push yourself beyond your stasis point to grow.
Saying your are a growing developer because you have done it for so long is like saying that since you have driven for 20 years you are a great driver. Well maybe you have driven for 20 years in small town Iowa but you are certainly not ready for the Indy 500 or even downtown Chicago for that matter.
I like your line “Blogging more accurately represents exhaling knowledge to those around you.” I would like to extend that idea. Blogging, or teaching, or explaining forces you to confront the details of the topic. While still in our heads these ideas are gaping holes that we have somehow managed to mentally spackle over. As soon as the words leave our mouth the spackle disintegrates and we realized how little we actually know.
I will often stop a random person at my office, dev or not, and explain to them my problem and the possible solutions. Typically I get a blank stare…Doesn’t matter. Simply verbalizing my thoughts helps me form new previously undiscovered connections. I also like to host brown bags where I present a topic I have recently been studying. The team thinks its great because they get to learn something new but what the don’t realize is I am doing it simply so I can understand it.
How does the joke about the professor go? “I don’t know what is wrong with these students! I taught them this stuff once and they didn’t get it. I taught it to them again and they still didn’t get it. I taught it to them a third time and now I get it but the students still don’t understand!”