We had 4 of these operation in our school.
All failed because dust gets through the filters into the motors.
When heat builds up with constant use the motor suspension rubber deforms (permanently) and allows dust into the motors. This in turn cause the motor to fail.
This is a commercial vacuum. Using it for long periods shouldn't be a problem.
Regular cleaning of the bags has not helped. Motors are half the price of the unit to replace.
The motor suspension kits if you catch the issue early are in very short supply from Nilfisk.
Just shake the vacuum up and down to see if your suspension rubber has deformed.
You can feel the motor move around.

It does a good job at vaccuuming dusts. This is the type that you wear on your back which I think is very convenient since you can access more areas and can move around easily. The cord is quite long as well so I was able to vaccuum my 2 story house without unplugging too many times.

I love backpack vacuums due to the ease of operation and speed that you can around in, compared to floor machines. Nilfisk is an excellent brand and this backpack has super suction and a sturdy design. Highly recommend to anyone who wants to get the job done quickly and easily!