Vinyl composition tile doesn't shine on its own. What you see in a glossy school hallway is the floor finish, several thin coats of it, sitting on top of the tile. When that finish gets scratched, yellowed, or packed with dirt, the floor looks tired no matter how often it's mopped.
For most buildings, a full strip and refinish once or twice a year is about right. Busy cafeterias, main entrances, and hallways that take boots and salt all winter often need it twice. A quiet office break room might go eighteen months or more.
The bigger factor is what happens between strips. A scrub-and-recoat, where we deep scrub the top layer and add fresh coats without stripping to bare tile, costs less and takes less downtime. Regular burnishing restores gloss in an evening. Buildings that keep up with both can stretch the time between full strips considerably.
Signs it's time for a full strip: the floor looks yellow or gray even after cleaning, dirt is visibly sealed under the finish, the finish is peeling at the edges, or burnishing no longer brings back the shine.
The best time to schedule is when the room can sit empty overnight so the finish can cure. For schools in Westborough and MetroWest, that usually means summer break or a long vacation week, and those dates book up early.