I had a pair of them several years ago. Gave them to a friend who really liked them. I like the eastern newts in their Red Eft stage far better. Ive had hundreds of them when I was younger. Have a few Adult Eastern Newts in my pond.
And yes, 10 years sounds about right. Though you never know how old they are when you get them. I never really followed the life cycle of the Fire-Bellied Newts, But with the Easterns, they spend 2-3 months in their larval stage, which is very similar in appearance and color to a mud puppy. After a few months, the larve lose their gills, develop sac like lungs, and move to land. this is called the eft stage, and during this stage, the newts become bright orange. They spend the next 2-3 years on land before changing to a green color with yellow bellies and returning to the water, where they will spend the rest of their lifes (10-12 years).