The last few years have served as an important reminder of the importance of not only washing your hands but doing so thoroughly. Has that lesson stuck with you?

There are fun ways of timing the process, like singing the “happy birthday” song twice, but some people have developed such a consistent routine that they don’t need mnemonics. Others might find the whole thing a bit excessive — are your hands really any cleaner after 20 seconds instead of 10, especially if you’ve been home all day? Well, yes, says the science, but sometimes putting knowledge into action takes more effort than we’re willing to put in.