Mary Isham retired last week after 20 years with the Checotah Post Office. She started her career with USPS Dec 25, 2004. “I was a stay-at-home mom of four kids until my youngest started school,” Isham said. “I decided then it was time to go to work. Though I had a bachelor’s degree in education, I decided on working with the USPS because my sister was already working for the post office. So I sta...