My roofers used a magnet to collect them. I found maybe two or three after they left. I checked recommendations on Nextdoor app, and got three quotes. The owner came out for the quote, got up on the roof to inspect, and he was also there for the job. 2000 sf roof, they started at six AM and were done by lunch, they had another job after lunch. I've seem some roofs in the neighborhood take three days.

I was very happy with the job they did. $12,000.

Edit: I should have said that the price included replacing two small skylights--which he insisted on doing "for free" because he said they always fail around the same time the roof gets replaced--removing an old swamp cooler and patching the hole, and adding four turtle vents. So, a little more than just replacing the shingles.