Lily Friedman, a 95-year-old pianist and teacher, has had a rollicking career spanning more than seven decades. But in quiet moments, a thought nags at her: Has she already reached the top and begun to decline? She doesn't want to go out with students dissatisfied or performances faltering. Then again, she doesn't want to stop at all.

After graduating from Juilliard in 1952, Ms. Friedman built a thriving career, at one point juggling as many as 50 students and regular concerts. Now she has fewer than a dozen. Her losses have come incrementally: stepping down as artistic director of Summer Trios, the chamber music organization she co-founded; parting with her red Mini Cooper at 92; and ending her annual New Year's Day fund-raiser when stamina faded.

After surgery in 2022, she began needing a cane and round-the-clock caregiver. Her vision and hearing are waning. Still, Ms. Friedman remains the draw at Summer Trios, held at Franklin & Marshall College in Lancaster, Pa., where nearly 100 participants attended in June. She mentored groups and performed Brahms's Piano Quartet No. 3, though some mentees complained about her hearing. A post-performance cake felt like a retirement party — a second year in a row.

By 2030, 74 million Americans will be over 65, and more will face this same precipice. Ms. Friedman is guided solely by her passion to keep playing.