* Look at their physical appearance. As people age, their skin becomes thinner and more wrinkled, their hair turns gray, and they may lose muscle mass.
* Listen to their voice. As people age, their voices may become higher-pitched and weaker.
* Ask them about their life experiences. This can give you clues about how old they are, such as when they graduated from high school or when they got married.
* Check their identification. This is the most accurate way to tell someone's age.
It's important to remember that not everyone ages at the same rate. Some people may look younger or older than they actually are. Additionally, there are some medical conditions that can cause people to look older or younger than they are. If you're not sure how old someone is, it's best to ask them.