I’VE been writing on some weighty topics lately — too little money, too many choices, too few jobs. It’s time, I decided, to move on to some questions that haunt me almost every day.

How much soap should I put in my washing machine and dishwasher?

Do I need to do more for my dryer than clean that little pull-out lint catcher?

Should I rinse my dishes before putting them in the dishwasher?

Most of us learned how to use a washing machine or dishwasher in our parents’ house many years ago and haven’t really changed our methods, even though most appliances have evolved radically since then. We rarely, if ever, read the manuals when we buy a new one or glance through the instructions on the box of detergent or bottle of dishwashing liquid.

But because we’re probably using these appliances incorrectly, our dishes and clothes may not be coming out as clean as they could be. And we may also be damaging the machines.