How do you know when it's time to get therapy?

I’ve been thinking lately that my life is getting pretty complicated and seems to be slowly going downhill. I’m a smart woman with a lot of common sense and I could help almost anyone fix their problems. I love giving advice and helping people get back on track. Problem is, when it comes to taking my own advice I’m not so great at it. Is it time for some outside help? A therapist? Has anyone else gone to therapy and found it to be helpful or a waste of money?