To me, being successful means...
Finding a job that healthily challenges me and that I enjoy (it doesn't have to be something that I have a burning passion for), that works with my schedule and lifestyle so that I can still take care of my mental and physical health. That's very important to me.

My definition of success has changed over time. 
My previous definitions of success hardly incorporated failure. I avoided failure like the plague, which in turn actually inhibited me from truly succeeding. I avoided taking certain risks that would have challenged me in a healthy way, had I succeeded or failed. I now understand that failure is both inevitable and necessary to be true to your dreams and goals , and succeed.