The bigger problem, unacknowledged in this rehash of old advice, is that modern synthetic laces are slipperier than old fashioned cotton ones. They last longer but they come untied far faster, particularly if they are round cord. There are better knots than the slip-reef for shoes. A “double-loop shoe bow” (twice around the held loop with the free end before tucking through) is an improvement. If combined with a double cross-and-tuck first (a two-turn overhand knot), your shoes will stay tied even longer.