It’s not just a bunch of space guys sitting around cussing like longshoremen; DAMs play a crucial role in ensuring Station and crew safety. Here’re more details:
Debris avoidance manoeuvres are planned when the probability of collision from a conjunction reaches limits set in the ISS flight rules. If the probability of collision is greater than 1 in 100,000, a manoeuvre will be conducted if it will not result in significant impact to mission objectives. If it is greater than 1 in 10,000, a manoeuvre will be conducted unless it will result in additional risk to the crew.
Debris avoidance manoeuvres are usually small and occur from one to several hours before the time of the conjunction. Debris avoidance manoeuvres with the space station require about 30 hours to plan and execute mainly due to the need to use the station’s Russian thrusters, or the propulsion systems on one of the docked Russian or European spacecraft.