The word space has ex­actly one pur­pose: to cre­ate hor­i­zon­tal clear­ance be­tween two words. Like­wise, the space bar has ex­actly one pur­pose: to in­sert a sin­gle word space.

Don’t use the space bar as a gen­eral-pur­pose white-space dis­penser by hold­ing it down and watch­ing the cur­sor glide across the screen. Though a calm­ing sight, it leads to an­guish when for­mat­ting the doc­u­ment. Use ex­actly one word space at a time.