* Main Sequence Stars Burn Hydrogen: Stars spend the vast majority of their lives in the main sequence phase, where they fuse hydrogen into helium in their cores.

* Helium Burning is a Later Stage: After the hydrogen fuel in the core is exhausted, a star enters a later stage of evolution where it starts fusing helium into heavier elements. This is called the red giant phase.

* Lifetimes Vary: The exact percentage of a star's life spent in each stage depends on the star's initial mass. Larger stars burn their fuel much faster and have shorter main sequence lifetimes, while smaller stars live much longer.

In summary: Stars spend most of their lives burning hydrogen on the main sequence, not helium. Helium burning occurs in a later stage of stellar evolution.