I like reading Reg Braithwaite's blog. I think he is quite insightful and a talented writer. Recently, he posted on why we are the biggest obstacle to our own growth. Another blogger (err...Sam) posted a follow up positing that it isn't age but arrogance that is our greatest obstacle.
Now, I will be first to step forward when somebody calls for the arrogant people to come to the front of the room (if my friends aren't pushing me there, first ;). I have also passed that magic age of 35 where, for some reason, people seem to lose the ability to learn how to program the clock on their electronic appliances (Twelve o'clock flashers). So, by all accounts, I should be hopeless.
But I don't think I am (introspection is always a challenging task). As I look back upon my career, it has been marked by a steady amount of change. What I've realized is that when I'm comfortable in a job, I become extremely uncomfortable. That consistently pushes me on to new and different challenges, which require learning to be able to achieve.
I would argue that it is neither age nor arrogance that are the obstacle. Those are co-symptoms to the real cause: complacency. Complacency comes when you've decided that you've paid your dues and you can rest on your achievements, and that can happen due to age, arrogance, position, or any of a number of other ways. The co-symptoms determine how you react to that complacency, but do not drive it to begin with.
Identifying whether you've become complacent or not is straightforward: if you are doing the same things in the same ways now as you were six months ago, and you find that comforting, then, in all likelihood, you've become complacent. Are you annoyed about changes in strategy or excited? Do new technologies make you groan or smile? Does a career change fill you with dread or excitement? Most people become very comfortable in their daily patterns, but that comfort, if not managed, will inevitably lead to complacency.
If you notice that you are becoming complacent, take action. Get out of your comfort zone. Learn a new technology (like Bungee Labs' :), take some classes, volunteer for new responsibilities at work, or find a new job. The point is that by stepping outside of your comfort zone, you break the cycle of complexity. Breaking that cycle removes our self-imposed obstacles and allows us to continue growing.