The Basics: Why do watches need this?

Why can't a mechanical watch just run forever without being touched?

Think of a watch movement like a tiny, high-performance car engine. It ticks hundreds of thousands of times a day. Over 3 to 5 years, the micro-lubricants dry up or turn into a gritty paste mixed with microscopic metal dust. Without servicing, the watch will start losing time, stopping randomly, or literally grinding its own gears down.