Rob:
Your grandma evidently knew the secret to getting the most out of her fine vacuum cleaner:
Get behind it and push!
I have seen so many people spend beaucoup bucks on Kirbys, TriStars, Air-Ways, Rainbows, you name it. And a lot of them ended up with houses no cleaner than before, because they didn't want to expend the energy necessary to use the damned thing, as if parting with so much money was going to make the house vacuum itself.
Having a fine vac is a wonderful thing, and I'd be the very last to disparage them, particularly since I own a TriStar. But you'd be amazed what a nice job even a cheap vac can do if you give it regular workouts.