I think modern psychotherapy mainly benefits people who are struggling with emotional problems including (but not limited to) depression, anxiety, friendship / marriage / family, shyness, OCD, drugs / alcohol and gambling (and other addictions). Some people (like myself) continue psychotherapy for a very long time or throughout their lives, not to resolve personal problems but because the self awareness and personal changes that are possible through psychotherapy can become a hobby, an occupation and a way of life.
I think anyone can benefit from therapy whether to solve personal problems or just to get to know themselves better. I don’t think everyone needs therapy and though for some it can become an essential and enriching part of life, I think its main area of benefit is in working through painful emotional issues.
I do not think psychotherapy is a ‘pill to be given’ or ‘solution to be applied’. If you decide to begin personal psychotherapy, I think you need to be committed to helping yourself. For sure, it is your therapist’s job to know the theory and apply it to the practice (and more) but whatever your interest in therapy, in order to get the benefits of it, you need to trust that it is likely to work, accept that change won’t happen immediately and could take quite some time and be prepared to contribute to the psychotherapy process; to think about answers to your therapist’s questions, to think about question to ask your therapist and yourself. Establishment of that commitment is half the battle won and your therapist is there to help fight the other half.