The phrase "time vet" refers to someone who has a lot of experience or knowledge about a particular subject or field over a long period of time. They are like experts or specialists in that area.
We get great references from out long time vet and still nothing. (thatmutt.com)
Just as much as you spend time vetting candidates, understand that potential employees also spend a lot of time researching a prospective employer. (thrivetrm.com)