How can a sourdough starter be 100 years old?

Question

I keep seeing sourdough starters all over socials. How can sourdough starters be many years old. Don’t you need to use the starter to make the bread? ELI5!

In: Other

Answer 1

None of my starters have made it past a week. I feed them and follow instructions, but they always either mold up or don’t rise and fall