When should a person consider a?boob reduction?

For pain relief: Breast reduction is not a cosmetic operation, but rather a procedure designed to reduce breast size to alleviate back and neck pain.

Severe back pain: Breast reduction surgery is very effective for large ptotic breasts that can cause neck and back pain, rashes, bra strap grooving, etc. It can usually be approved by insurance if at least 500 gm of tissue will be removed from each breast, and insurance companies typically take height, weight and photos into account. You have to document that conservative measures like physical therapy have failed.

A trade-off: if you feel that they are too large for your frame, or you are having symptoms of neck and back pain, should-strap grooving, and difficulty exercising - and you are ok with the resulting scars, then a breast reduction might be reasonable for you. See a board-certified plastic surgeon in your area for a consult.