Hair transplant is 100% permanent. Planted hairs are going to stay there for life. Why? Because hairs used in the hair transplant procedure are taken from the permanent zone, they are going to last forever.

In Hair Transplant, whether it is by strip or FUT method or by FUE method, the donor hairs are taken from the above mentioned permanent zone of the scalp. In simpler terms back of the scalp and side of the scalp and not from the front and top portion of the scalp. This is done for a simple reason: Hair from the permanent zone areas are not affected by the process of baldness and hence if they are planted over the bald areas, good hair will grow. Nothing is wrong with the scalp/skin in the bald areas. This is the reason Hair Transplant is a permanent method of Hair Coverage
And yes: The planted hairs grown naturally: You can cut them, dye them, shave them off-they will grow back again just like your original hairs.