I'd love a good vac. The one I have now is ok. Sucks better than mum & dad's Vax (don't tell dad that ), but the head cracked around the pipe with in the first few weeks, so it comes off as it pleases, & the extender bit on the pipe stuffed up & wouldn't hold not long after that.
IME as long as you clean out all the filters regularly they will go forever (something MIL taught me, I notice the difference every time!). I probably do mine every month or two. When ever I notice the suction isn't so great.