Things unused

I never used algebra in my life.
How many things do we learn we never used? Were they worth the learning?

IMO there are two kinds of education: memorizing information and learning how to do things. Information is useful to us only when we need it often enough that looking it up would be a waste of time, but skills can't be acquired quickly through research, so they are often very useful even if use them only rarely. For example, I haven't done any swimming for at least twenty years, but if I suddenly found myself in deep water, I would start swimming instinctively, whereeas someone who had never learned to swim might drown.

However, algebra is a skill, not a body of information, just as doing arithmetic is, and having learned both in elementary school can be useful in solving number problems in general throughout our lives.