HALT! Take a second and think about the last thing you did to become a better teacher other than your district/state-mandated PD.
When did you go out of your way to do something that will help you become more knowledgeable in your content area or help you find new and more engaging ways to teach your kids?
Just because we are teachers does not mean we should stop being students.
If you stop being a student you will become stagnant or even stale. The biggest injustice we can do to our students is to become stale. By stale I mean you think you have everything down and you recycle lessons year after year and forget to do things that will help you become a better teacher.
One thing I try to do as a younger teacher is to challenge my older colleagues to stop being so stale. In PLC's I challenge them on certain things, respectfully of course, but some are nearing retirement and are literally just counting down the days until they are retired, which results in them becoming stale.
I challenge you to do something today to make yourself a better teacher. It does not matter if you have been teaching for ten years or ten days, you can always find something to do that will help you become a better teacher. Go observe a teacher in another school, go out of your way to find a conference that will help you with an area you think you need to improve in, go join a professional organization, DO SOMETHING.
Do NOT let yourself become stale. Your kids can see it in your demeanor and your teaching style if you've become stale, especially if you're a bit older. Stay relevant. Stay fresh. Stay dynamic.