When I turned 40 I had a mammogram that was so painful it left me bruised. Then, since I had a small cyst, I was talked into an aspiration which I couldn't afford at the time and spent a whole year paying for. So I didn't go back for 20 years.
Finally at 60 I did get another mammogram and insisted they stop pushing when it got too painful. They CAN do that now! A couple of years later I had a small IDC. I was just lucky nothing came up in the years I didn't get checked.