I bought my first vacuum cleaner (a Eureka canister) used for $45 in 1983 which lasted 15 years or so.  I've had several since, including a $500 Hoover upright with powerbrush attachments.  A friend recommended the Mighty Mite as a lightweight but powerful machine when tennis elbow made it difficult to move the very heavy and awkward Hoover upright.  While my Roomba does the bulk of household cleaning it doesn't totally replace a conventional vacuum cleaner especially if you're a person like me who, at any one time, has a home improvement project going.  I needed something to clean sawdust as it was coming out of the saw and to catch concrete dust as I drilled holes in the concrete ceiling (if I let this reach the hardwood floor, it would act quickly like rough sandpaper and destroy the floor's smooth surface).  I paid about $50 or $60 for a reconditioned Mighty Mite and expected to get a low-power machine that I'd need to replace in a few months.  Instead, I got the most useful and most powerful vacuum cleaner that I've ever owned or used in my life!  It's a brilliant machine.  What use is a decent vacuum cleaner if it never gets used because it's too heavy or cumbersome to use?  This machine is always ready to go and has incredibly powerful suction.  It's a bit noisy but I don't run it for more than 5 mins at a stretch so that's not a big problem for me.  I can take it anywhere with ease.  The ONE negative about this bargain-priced machine is that the flexible hose can't withstand the very powerful suction of the motor. This means that within a few months, the suction was regularly closing the walls of the hose in on itself, blocking the airflow.  The only remedy was to turn the machine off and twist the hose around until it regained its proper shape.  This got progressively worse so I bought a new, reinforced hose specifically designed for the Mighty Mite (from Ebay) for $30 or so.  I baulked at the cost, given how little I paid for the whole machine but it was well worth it as I now have the perfect machine for me.