'par for the course'
refers to what one could expect based mainly on previous experiences.
It is a well known idiom,but not that commonly used.
It derives originally from golf courses, meaning the expected number of times a good player in golf will hit the ball to get it in all the holes.
"- They replace a lot of workers in the firm lately.
- It is par for the course around here, in a place with such a high turnover."