Have often wondered why people bother with these, as I always weigh my cases by standing on the bathroom scales. But just come back from a trip away and realised that these would've been handy on the return journey (no scales available). My luggage allowance was 20kg and my case weighed in at 19.9kg! I was lucky on this occasion but won't be taking any chances in the future! Nice and compact and handy little tape measure makes this the perfect travel companion.