Are you using the vac on hardwood/tile, or mostly carpet? I was so upset that our vacuum wasn't working well a few years ago, especially because my mom had the same vacuum my entire childhood. The local vacuum store woman (who seemed to really know vacuums!) said that those made these days are made to last a few years at most.
We bought a Miele from her about 4.5 years ago, because they are made to last in the 10-year range - overall, less money invested over time and less waste throwing junk in the landfill. I am a total fan of the Miele - it is fantastic. I have mostly hardwoods, so I just have a carpet head attachment that is air-powered for the few rugs. If we had more carpet, we would have invested in the higher-end model with a power-cord-powered rug attachment.
I think you should visit your small, local vacuum shop and think about longevity. Most of what is sold these days is just crap that won't last.