I believe knot-tying would be a great, life-long skill to have, especially being able to know which knots work best for different situations, like when the rope is thick and not very flexible or bendable.
I have lots of nylon rope and fishing line of various diameters, but don’t know where to begin and/or the best way to get started. My goal is to make this a long-term hobby and spend 1-2 hours per week improving my knot-tying knowledge, skill, and speed.
The Bear Essentials has good knot-making videos on YouTube. My personal opinion is that you shouldn’t learn knots just for their own sake - instead, figure out which ones best fit the needs in your own life. The best way to remember a knot is to actually use it.
Ones like the bowline, alpine butterfly, and trucker’s hitch are immensely practical and easy to untie. I keep a piece of paracord on my desk at all times just for practicing knots. It’s definitely a use-it-or-lose-it skill.
These are probably the three most important knots you could learn.