Exposure hours is a concept coined by Jared Spool in his article Fast Path to a Great UX — Increased Exposure Hours. Spool describes Exposure hours as the “silver bullet when it comes to reliably improving the designs teams produce”. He desribes exposure hours as:
The number of hours each team member is exposed directly to real users interacting with the team’s designs or the team’s competitor’s designs. There is a direct correlation between this exposure and the improvements we see in the designs that team produces.