I needed to install 12 clips in boxes on a plasterboard ceiling. I know that every drywall cut at the top creates a huge mess, you have to cover everything which adds time and money to the job. I bought this after reading so many good reviews and it's worth its weight in gold. As others have mentioned, after 1 or 2 holes when you need to look through the bowl to hit the target you will need to wipe or rinse it with a damp cloth. And as mentioned, using a washer between the drill and the bowl saves the red insert in the bowl. It depends on what shank size your hole saw is, mine was 1/2" so I used a wing washer with a 1/2" hole. If you like keeping it as cheap as possible, a milk jug lid should make a good washing machine. When I put the hole saw in the drill bit, I made sure the bowl could still turn, but you have to get as close as possible to avoid dust getting into the hole. I drilled slowly, glad the dust didn't fly out. Well, as a tip that will be helpful to reduce the amount of dust entering through the hole in the bowl, milk jug snap lids are the perfect shim for the bottom of the hole saw in the bowl, just drill a slightly smaller hole in the lid so it fits snugly around the tail.