How long do you burn-in Printers after you repair them?

Hi,
I’m doing research,
I’m a manager in large repair group (75000 pcs per yr)We repair 1400 printers (lasers,multifunctions,line printers,impacts ,label printers) each month. Our average burn-in time after repair is 1 hour 20 minutes.

If you work in a repair facility I am interested in how long you burn -in printers after repairing them. I appreciate any feedback.
Thank you
Wayne Overcash