I've been going to counseling for almost 14 years and I can honestly say that therapy has completely changed my life. There have been times when I could barely get from session to session, and there have been times where I've gone several weeks without an appointment and felt fantastic. No matter what was going on, I stuck with it, and it has improved my mental health significantly.
Even if you feel great, talking to someone about how you're feeling will only benefit you.
Talking to friends and/or family is great, but going to someone who has absolutely no connection to your life will change the way you think. They can give you their thoughts on something without being afraid of hurting someone's feelings or being biased. They won't judge you if you sob for an hour, and they won't care if you have nothing to talk about but good things happening in your life. In fact, I guarantee they'll want to celebrate with you, even if they don't know you on a personal level.
Going to a certified therapist is also a great idea because they are educated on the subject and know what to say and when to say it. They know what to recommend, positive coping skills to use, give quite literally expert advice, and everything else that you can't necessarily get from a family member or friend if they're not a certified counselor. Think of it this way — if you have a cut on your arm, a friend or family member could look at it and recommend different treatment — a band-aid, stitches, etc. But if you go to a doctor, they can assess the situation and give you the best solution because they know what they're talking about. They're a professional in their field! You trust them, just like you should trust that a therapist knows that they're doing and wants to help you through whatever you're going or not going through.
Therapy isn't just for "broken" people. Let's be honest — we're all a little broken from time to time. In our times of need, in order to keep a healthy headspace, talking to someone about your problems will open up a world of opportunities for coping, and may even bring out underlying issues or memories you didn't know you were harboring in the back of your mind. You'd be surprised what can come up if you start talking openly and candidly about your life.
Whatever you're dealing with or going through, talking to someone about it will help. The more you get out in the open, the more you're able to work on. After nearly 14 years of going to therapy, I can confidently say that I am as healthy as I am because of the positive treatment I've gotten. Even if it's just one time, talk through your thoughts with a certified therapist, and watch the growth that comes from it.