[sunrunner]

Personally I make sure to always carry around a string and some scissors, so any time I need an arbitrary measurement I can just cut the string to the length of the thing I want to measure (making sure to label it in case of multiple required measurements), then measure the cut string later. Simple.

Although I still haven't figured out the best way to do that in reverse (when someone wants a specific measurement and I cut the string from that number), though I was considering a scheme where I start with strings of known length up-front then repeatedly cut successive halves until I converge on the desired number, accounting for cut accuracy and require precision.

[madcaptenor]

Maybe you could start off with a long string and then mark off its midpoint, the midpoints of the halves, and so on. Then you wouldn't have to cut a new string every time you want to measure something.

[saalweachter]

There's also the concept of a story stick.

When working on a project where you need a bunch of things to be the same, you take a stick and mark on it at various points the dimensions you're using -- when working on a house, it might be things like the heights of outlet boxes and switches, the width and height of rough opening for doors, the height of window sills, etc etc.

Then, you just use the stick as the reference, using the marking for outlets to position all of the outlets instead of measuring the height of the floor in inches or millimeters or cubits or whatever each time. It's kind of like a measuring jig.

("Measure once, cut twice" is a superior methodology which has been unfairly maligned for generations.)

[Dilettante_]

What, and use the same thing to measure stuff anytime you measure something? Like that's ever gonna catch on! Next you're gonna tell me to use my lower arm as a measuring stick!

[layer8]

The span from my thumb to my pinky in a “measuring position” is 20 cm (and is easily repeated by moving the thumb to the pinky and then stretching out the pinky again). The length of my “thumbs up” hand is 16 cm. The width of my fist is 10 cm. The length of my pinky is 6 cm. The width of my thumb is 2 cm. This allows me to estimate distances between ~2 m and 2 cm pretty well. Knowing your foot/shoe length also comes handy sometimes.

[lproven]

> The span from my thumb to my pinky in a “measuring position” is 20 cm

26 cm for me. I can stretch to 27 cm quite easily, though.

> The length of my “thumbs up” hand is 16 cm.

18 cm.

> The width of my fist is 10 cm

Same.

> The length of my pinky is 6 cm.

7.5 cm.

> The width of my thumb is 2 cm

2.5 cm.

I guess the main thing between mine and more typical hands is my long, fairly slender fingers, then.

[testing22321]

I do the same, but my piece of string has little lines and numbers telling me how long a thing is.

[woliveirajr]

Reverse: perhaps carrying a measuring tape [0] ?

[0] https://www.amazon.com/Measure-iBayam-Measuring-Measurement-...

[Lio]

How long is a piece of string eh?

That works but with a piece of paper you can tell the time too, so long as you get a nice man to write it down for you[1]. ;)

1. And now the confusion of having to explain the Goon Show: https://www.youtube.com/watch?v=rLQhQSiDR-k

[mhb]

So besides the string and the scissors, you also need a marker that can write really, really tiny?