For better or worse, cooking will always involve a certain amount of measuring. Usually these measurements are either by mass or volume, but sometimes dimensions come into play, and I am terrible at estimating dimensions.
That's flour on it. Photo: Claire Lower
For this reason, I keep a retractable measuring tape in my kitchen "odds and ends" drawer, and break it out whenever I need to know how long, wide or deep something is. Any tape measure will do, but I like the one I took out of my "recently divorced woman" toolkit, because it is stiff and lockable, and I saw someone use one like it on the Great British Bake Off.
With your handy measuring device, you can measure steak thickness, dough depth, crust area, dice size, and figure out which of your cake pans is actually 23cm. I mostly use it in baking, but it's always nice to know how thicc your steak is.