The typical first response by school districts when faced with daunting teacher shortages has traditionally been to rehire their retired teachers. It's a finger-in-the-dike solution that does little to ameliorate the underlying reasons why these shortages never go away.
No matter--districts like this approach so much because retired new hires often start steps below their actual experience level on the district salary schedule. Districts think they're getting great value for their money. In Utah, the Jordan School District "saves" around $8,000 for every retired teacher it recruits from another district because the Jordan contract, like most teacher contracts, caps previous teaching experience outside of the district at a middle point on the salary schedule.
Rehired retirees also benefit, making $20,000 to $30,000 more than they did before retirement due to the combination of a salary and generous state retirement benefits.
It is not, however, a sweet deal for taxpayers, who are paying a lot for stopgap measures and getting little in the way of long-term solutions. And given ample research findings that show that districts don't get much more value from teachers with 20 years experience versus those with just a few years, students aren't reaping much benefit either.