How old are you supposed to be to do this? Is it more useful to use this than get a top surgery?

Since every individual is unique both in anatomy and with objectives, a personalized approach can be planned and your goals met with surgery, I hav had many binary patients come in for surgery and results range from moderate reduction to completely flat chests and even without areola-nipple reconstruction.

Thank you for your question! If you are a non-binary person who is not looking for traditional top surgery but still seeking something similar that can help, there are a few options to consider based on your goals.
Chest binding or wearing certain compression garments might be another way to achieve a desired appearance without surgery. These non-surgical methods can be adjusted depending on your comfort and desired appearance.
One possibility is chest contouring or shaping procedures, which can create a more masculine, feminine, or neutral chest appearance without the full scope of top surgery. This could include procedures like liposuction to remove excess tissue.
It's important to consult with a knowledgeable and supportive surgeon who is experienced in working with gender-affirming procedures, transgender and non-binary individuals. They can help you explore different options that align with your personal needs and identity. I discuss with my patients the options of: preserving the nipple-areola (or not), targeted nipple reinnervation if free nipple grafts will be used; and liposuction (or not).
Krishna Vyas, MD, PhD, MHSHarvard and Mayo Clinic Trained Aesthetic and Plastic SurgeonNew York, New York