A name’s length should not exceed its information content. For a local variable, the name i conveys as much information as index or idx and is quicker to read. Similarly, i and j are a better pair of names for index variables than i1 and i2 (or, worse, index1 and index2), because they are easier to tell apart when skimming the program. Global names must convey relatively more information, because they appear in a larger variety of contexts. Even so, a short, precise name can say more than a long-winded one: compare acquire and take_ownership. Make every name tell.