Visible crew/equipment: In the beginning, when Joel "first" goes to Kate's apartment for drinks and Kate is discussing her worry of wasting time, when the shot switches from a side shot to a straight shot, a boom mike shadow moves above Kate's head.
Visible crew/equipment: When Clementine storms out just before the bit where Joel chases her down the sidewalk he gets in his car. The shot from beside the car shows at least two shadows of the crew moving around on the car.
Visible crew/equipment: When Joel awakes he looks at his dented car. When he walks in between the cars to look at the back of his own car, you can see the reflection of a boom mic being poked round to pick up his footsteps.
Answer: When the techs are packing up then next morning, the young guy (Kirsten's boyfriend) says something about having to get to the next job. So its safe to assume the erasure takes a good 8 hours to complete normally but Joel kept fighting them so it would have taken a little longer.