Nightclubs and resorts everywhere are swamped with reservation requests to host over-the-top birthday parties. But they’re not for turning 21; they’re for 40th birthday parties. Turning 40 used to be a birthday milestone no one celebrated because it meant getting old. But today, the Gen-Xers who are hitting the big 4-0 are celebrating like they’re teens, with fancy parties, wild Vegas trips, and Cabo getaways. 

So why is 40 the new “party age?” Experts say it’s because Gen X-ers consider 40 the new 30, mentally and physically. And they want to throw a crazy bash to show they’re still going strong and can have fun. Dr. Richard Settersten is a professor of aging at Oregon State University. And he says that Gen-Xers were the first generation to delay getting married and having children until their 30s and 40s. So they feel younger because a lot of them are newly married and have toddlers running around. They also feel younger physically. Doctors say that people turning 40 today will live an average of six years longer than previous generations because they take better care of themselves.