Clothes may represent yourself, the way in which you see yourself and how you think (or are afraid) others may see or consider you.
If in the dream you’re wearing old clothes this can symbolize that you are a bit anxious about your attractiveness to others. Or it can mean that you have to change your opinion (which is “old”) about something.
Similarly, if you dream of changing clothes this can mean that something has recently changed in your life.
Lastly, if in a dream you see someone else wearing your clothes, this may mean that you feel that person very close to you.