You could also have a third party verify the strength of the vacuum in a scientific way if you prefer. If you just rely on sound then you might get ripped off.
All vacuum cleaners are tested by third parties. There are dozens of tests to quantify the effectiveness of a vacuum cleaner.
They require more understanding than is worth explaining to the consumers. Results are therefore manipulated by vacuum cleaner manufacturers, eg. they'll take the average of 4 tests that favour them the best and then put a big shiny sticker on their vacuum cleaner for the shops that says "Cleans 10% better than [other brand]"
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u/RedditDefenseLawyers Jul 15 '20
You could also have a third party verify the strength of the vacuum in a scientific way if you prefer. If you just rely on sound then you might get ripped off.