In many, perhaps most, systems, quantitative description down to a precise figure is either impossible or useless (or both). For example, estimating the distance between our galaxy and the next one over is a matter of knowing not the precise number of miles, but how many zeroes are after the 1. Is the distance about 1 million miles or about 1 billion? This thought habit can help us escape useless precision. - Shane Parrish “An order-of-magnitude estimate of a variable whose precise value is unknown is an estimate rounded to the nearest power of ten.” (related: order of approximation, back-of-the-envelope calculation, dimensional analysis, Fermi problem) - Gabriel Weinberg
Shane Parrish's Farnam Street Mental Model Guide https://www.farnamstreetblog.com/mental-models/ --- Gabriel Weinberg's Mental Models I Find Repeatedly Useful https://medium.com/@yegg/mental-models-i-find-repeatedly-useful-936f1cc405d