I can't imagine sailing in (for example) Maine in fog, rain, wind, and tide without a lot of instruments. There are people still sailing who remember doing it with electronic depth sounders, speed logs, or anything but their senses, a watch, and compass. I'm not that much of navigator. A man's got to know his limitations.

If you sail in the Chesapeake, you can get by with just depth sounder and compass in most situations. Instrumentation done properly is like something akin to sex. You should start slowing without a lot of complications and work up to more intense.... [I think this anology can only get me trouble beyond this. :^))) ]

Remember, there's a tradition that the best sail trimmers, helmsmen, and sailers usually come from boats with nothing but a bit of yarn to let them know where the wind is and the realization that failing to pay attention to the helm, sails, boom, wind, and seaway will end-up with them in the water. Those are dingy sailors.

The great Viking and Phonecian sailors who transited oceans without instuments, charts, or much else make me look like "pupply". Of course their life expectancy was less than 2/3rds of my current age ;^)))

Anyway, such items that seem like extravagences can benefit ones performance, safety, and enjoyments -- but it comes with a price of both time and money.