One time to be extra scrupulous is after maintenance has been performed. Of the hundreds of test bikes I have received in a quarter-century of testing them, three arrived with loose drain plugs. All had just left the in-house service facilities of major motorcycle manufacturers. Since some service people are offended when I start double-checking their work, I have learned to ride around the corner before I do it, but I usually don't go much farther than that. On my own bikes, I keep an eye on things that have been removed or replaced recently. For example, I pay extra attention to the seal of a new oil filter and double-check a recently installed fastener to be sure it isn't loosening up. One time I discovered that a front axle clamp had fallen off. I know two riders who adjusted chains and shortly thereafter lost their rear axle nuts, though one took over 100 miles to depart the bike. Rechecking those recently serviced maintenance points avoids such problems.