Should my husband get a vasectomy at 29?

We have 2 kids(one is 12 and the other one is 7), at the moment we do not want more kids but the doctor told him he has to think about it because he is still young and some people who gets a vasectomy at a young age go back after 10 or 20 years because they want more kids or because they re marry and sometimes they can't have more kids later. She also told him that if he was sure he wanted to have it done, that he could go to a clinic and have his sperm frozen just in case he wanted to have more kids later on. What do you recommend? should he have a vasectomy at 29?