have been through the mill

To have been subjected to some ordeal, difficulty, or harsh treatment; to have undergone an intensely unpleasant experience. Between getting fired from his job, losing his mother to cancer, and having his house repossessed by the bank, poor Jonathan's really been through the mill this year. You'll all feel like you've been through the mill by the time you finish bootcamp, but it's the only way to make you into soldiers. The coach is renowned for his strict practice regimen, so you know any of his players have been through the mill.