half a lifetime; one's life so far
Refers to a long period of one's life, often with a reflective or narrative tone. Can mean roughly half of one's expected lifespan or the years lived up to the present.
He spent half his life completing this research.
Looking back on my life so far, I can say I have no regrets.
He wrote an autobiography looking back on his life so far.
She has devoted half her life to music.
He led a life full of ups and downs.