Well - once you own a house you will need more. I use algebra and trigonometry every time I work on the house. If you ever learn to cook you will use algebra to figure put how to expand your receipes using non whole numbers. You probably won't factor a quadratic equation though.

In terms of useless knowledge, calculators have made my expert use of sliderules and log tables obsolete. I also know how to fix skips in vinyl records - another obsolete skill. I'm sure I can think of more with some time.

Kathleen