People would ask me why I made pets of rodents. It didn't make sense to them that I spent money on housing the very creatures they set traps out for. She lived for about three years. The mice I took care of lived anywhere from two to four years. These creatures are very clean and relatively odorless, but if you aren't a nocturnal person, you shouldn't get one.
Hamsters sleep all day long, and are up all night chewing and running in their wheel.
They are generally cranky. I never had much luck with hamsters, but some people rave about them. They have short tempers and if you put two males together, they will constantly fight. One hamster per cage is plenty. They live about three years.