Here's why:

* Fuel Consumption: Stars fuse hydrogen into helium in their cores. The rate at which they burn through their fuel depends on their mass. Massive stars burn their fuel much faster than smaller stars.

* Nuclear Fusion: Larger stars have stronger gravity, which compresses their cores to higher temperatures and pressures. This accelerates nuclear fusion, causing them to burn through their fuel much quicker.

* Lifespan: While massive stars have much higher luminosity and are more impressive, they have much shorter lifespans, often just a few million years. Low-mass stars, on the other hand, can burn for billions of years. Our own sun, a mid-sized star, is estimated to have a lifespan of about 10 billion years.

Examples:

* Red dwarf stars, the smallest and coolest stars, are expected to live for trillions of years.

* Our sun, a G-type star, has a lifespan of about 10 billion years.

* Blue giant stars, the largest and hottest stars, have lifespans of just a few million years.