Accidental damage does happen, so each device needs a service plan based on lifespan, volume of usage, and replacement cost. Turnaround time, depot service, self serve, and comprehensive service contracts are just some of the considerations. Also some vendors only service certain makes and models meaning having to juggle multiple service vendors.

Selecting the right service plan is also affected by the law of diminishing returns - overspend and you'll be buying expensive insurance versus getting it right and coming out ahead in terms of uptime (as in field hours of use) versus having devices idled because there isn't, say a spares policy in place or a better turnaround time associated with that repair.