I was going to get a 1HP dust collector to use with the machines in my
garage/workshop. I was thinking I would replace my shop vac with the
DC so I won't take up too much space.

The person at the store said it is a bad idea to use my PC 5" random
orbit sander and a DC. Something about not enough air would get to the
DC and the air would cavitate making the suction poor. I really don't
want to take up space with a DC & a shop vac. I was going to add 3
feet of 2" hose to the 4 foot long 4" hose the DC came with.

Anyone have experience with using a 1HP DC and a 5" sander?