I will try to explain you in the most easiest words, why you will never lose your newly transplanted hairs again, throughout your life.
The reason is very simple. Even a kid knows that any human being does not loses hair from his back side of head (as shown in above picture). Those hairs are permanent in nature. In medical terms we call those hairs as DHT resistant hair or hormone resistant hair.
Now, in any hair transplant surgery (whether FUE or FUT), hair roots are taken from the back side of your head (also called as doner area), and planted to your baldness area (also called as recipient are). Since these hair roots are permanent in nature, when they are planted in your baldness area, the new hair which grow from these planted hair roots, also become permanent. You will never lose them again.
The hair that is planted has a natural look and feel. You can cut, dye or shave them like your normal hair. They will again grow back like your natural hair.
Please note a point here, that after 1 month of your hair transplantation you will temporarily start losing the transplanted hairs, and may continue for next 2 months. The temporary loosing phase is followed by permanent growth phase during which hair will continue to grow at normal rate. After the temporary lose phase, your transplanted hair will remain for life long life without any medication or maintenance.
Kindly note that, hair shedding (loosing the hair) after a hair transplant is a normal occurrence and is the body’s response to the trauma (hair transplant surgery), which is also called shock loss. When hair transplantation is performed with exceptional care by an experienced surgeon, the chances of shock loss are significantly smaller.
Point to be noted: The hair roots (follicles) that your surgeon transplanted, will never get thin or lost ever again. But your existing hairs (which were present during hair transplant surgery) will continue to fall. To stop the hair fall for those existing hair, you have to take some medication. Your Dermatologist or hair transplant doctor is the best person to advise you the medicine or treatment.