Welcome to the forum, Tess
On average, African clawed frogs live between 12-20 years in captivity. I haven't heard very many ACFs living that long, but it is possible.
African clawed frogs are really hardy in captivity and very few diseases affect them. Most of the problems are the result of poor husbandry. Both males and females will rap. The rapping is a metallic, buzzing sound that can be quite loud. Mine will rap every night, sometimes so loud you can hear them all over the house. If you have a female, she will sometimes emit a ticking sound, telling the male that she's not ready. They are mostly active at night. I have been keeping these frogs for many years and it seems the more I learn about them, the better I like them. Good luck and enjoy your frogs!
There are several people on the Frog Forum that keep ACFs and would be happy to answer any questions you may have.