When I began cycling I was very poor physical condition so that 200 yards was a struggle. Through determination (stubbornness) I kept at it over weeks and months and the miles began to accumulate on rides from 10, then 20 and 40 miles. On a 40 mile loop I was 20 miles from the house. It occurred to me that a mechanical failure on lightly traveled rural roads could have bad consequences. Gradually I added spare equipment as experience increased.
If you are intending to cross Asia on the old Silk Road, you will want a lot of extra stuff. For a typical day ride, say 40 to 65 miles, a tube patch kit and an extra tube, I usually carry an extra worn folding tire, a quick chain link and a few spare links, and some tools consisting of 3 allen wrenches to fit everthing on the bike, a tiny vicegrip and a screwdriver. For a weekend tour, further from home, a few more tools.