Will smartlipo triplex benefit fatty legs on a woman of 72 years?

As the skin ages, it loses both elasticity and thickness. This means that lipo techniques which work close to the skin surface, such as smart lipo, might cause the skin to wrinkle. You can certainly have lipo to reduce fat deposits, but the surgeon needs to stay away from the skin surface to avoid nasty wrinkles.

Hello. Smartlipo would effectively remove fat from the legs of a 72 yo candidate but in no way would I expect enough skin tightening to get a satisfactory result. Unfortunately,  I could not reliably recommend this procedure in this circumstance. It all depends upon your goals. Dr. Burnett

Liposuction can be performed almost at any age.  If you are looking for skin tightening, the smart lipo device probably will not provide enough for skin in a 72 year old.