How much has your style evolved over the years?

This is sort of inspired by my previous question, since I started digging through old photos of myself. Looking at pics over the years (and in many cases, months), I look like a completely different person. I changed my hairstyle, hair color, sometimes I’m tan, sometimes I’m ghastly pale, etc etc. I have been like a human chameleon over the last 15 years.
How often do you change your “look?”
Have you had a tried and true for a long time now, or do you frequently change it up?
How much do you express yourself through your style of dress?