Some people have one job during their life. I've had several.
I have been a labourer, tradesman, foreman, manager and owner. I have held both line and staff positions. I have been salaried, hourly paid, and worked on piece work. I have also been a commission salesman. Most of the variety is due to the nature of the construction industry rather than inability to hold a job. My longest period in one job was eight years.
NB: I should have a page about my incredible management skills. I'll get there one day.