For every misstep involving a substitute teacher, Hillsborough County School District officials and their contractor say there is a far greater number of positive outcomes.
Since 2014, they said, more than 1,000 Kelly Educational Staffing recruits have made the transition from substitutes to district teachers.
Sandra Denham, 64, went full circle.
Denham helped built a successful special education program at Plant City High School, but committed to early retirement at the end of the 2015-16 school year.
Like a lot of state employees, she wanted to cushion herself against payment changes in the state retirement system.
"As soon as I retired, it was like, this is not for me," Denham said. "I have to have a purpose in my life, and I truly love what I do. God knows, nobody does it for the money."
So she returned to Plant City High that August as a substitute.
It was an adjustment. Instead of teaching highly disabled students in a self-contained class, she taught more moderately disabled students who needed to be coaxed to learn. But she was impressed with the Kelly process.
"I had an excellent trainer," she said. "A lot of it was review for me, but the training was great for people who have not been in the system. I was not bored at all. I did not resent having to go through it, and it made me feel good about what substitutes were getting and how they were being trained."
After a year, she returned to the School District in the same job she held before. She is still involved with extracurricular activities, such as Best Buddies and Special Olympics.
And it was a thrill to make contact again with the parents of her special needs students.
"They're my heart," Denham said. "They're what keeps me going and keeps me motivated."