Insulation Removal Vacuums go through abuse. The obvious problems are caused by the foreign objects that are sucked through the hose (nails, pieces of junk, even brick pieces) from the attic.
The SILENT killer of a vacuum is failure to maintain the vacuum. Dust gathers around the engine, unlike most applications. While extracting the insulating materials, they create enormous clouds of dust. Here are some tips and videos on maintaining and tuning up your insulation removal vacuum machine.