Not spending presupposes homesteading, production or trade. These are the only ways in which one can have property to not spend. You are the homesteader of your body (energy, attention, muscle, blood, brain, feeling, choice). How else do you do anything with it without asking permission from anyone else? Once homesteaded, work toward production or trade. Aim for profit (what you acquire is worth more to you than that which you trade).
Spending involves either consuming or investing. Those are two very different ways to spend. Can you not consume so that you may invest? Some consumption is required, but so much of it is relative to psychology. I have met he who eats out sometimes twice a day. And I have met he who eats cheap noodles or oats twice a day. How many calories (energy) do you want? How much rest (non-work) do you want? What are these worth to you compared to what you might do with that which you might produce or trade for profit?
Why do individuals choose saving over investing or consuming? Uncertainty about the future. You will restrict consumption in the present if consuming in the future becomes more valuable than consuming in the present to you. You will restrict investment if the likelihood of profit diminishes too greatly.
After deciding to save it is an interesting question as to what is to be saved? To my mind, and I am not alone, saving virtue (temperance) is worth way more than saving calories. In a similar analogous fashion, to my mind, saving precious metals is worth way more than saving dollars. But in the latter, I am like the obese having decided on temperance intellectually but with passion and will still devoted to calories. I find it hard to let go of dollars (which my government has stated explicitly it would like to keep at 2% inflation which will most likely continue in the form of debasement) in the same way the over-eater finds it difficult to let go of calories. It is not intellectually difficult. It is a matter of feeling and will.