The problem with this is there is no direct answer. Even for trans people. I am one such trans person who doesn't feel like they need to go through any surgery to change their body. Unfortunately, that surgery can save lives. I'll only stress the can. So if some one should change their sex is completely dependent on too many factors. But for trans people, generally speaking, Probably? Maybe? I assume so.
All surgeries come with complications. By taking a sex changing surgery, someone will be subject to the complications that can result from it. On top of that, they may regret the surgery. Unless a surgery is needed, there seems no reason for someone to change their sex. Their not going to die from any natural causes as a result from keeping their body the way it was born.