I have two gerbils since July 2018 called Patrick and Simon.
In the beginning, I kept them in a case but they kept escaping so I decided to let them run free.
This has had mixed results.
It is nice to see Patrick and Simon all over my home either standing up on back feet watching or running around at full speed.
The downside is they like to bite stuff, ideally just paper and cardboard, but unfortunately they also enjoy electrical cables which means have sometimes quite the troublemakers!
But overall, I am very happy they have the freedom of my home despite the trouble they caused.