It’s been nearly 51 years since Billy Joel recorded the song “Piano Man” — five decades of performing and merchandise for all occasions. As Mr. Joel, 75, will perform his 150th show at Madison Square Garden, the final performance of his 10-year-residency, fans have been gearing up.

Five decades of performing means a lot of T-shirts sold — more than 10 million, in the estimation of Claire Mercuri, a spokeswoman for Mr. Joel — and that’s just the count for licensed wear.

The musician doesn’t have a favorite item — they’re all his “children,” Mr. Joel said, through Ms. Mercuri, which he also says when asked to pick his favorite song.

There are also Wayfarer-style sunglasses with Mr. Joel’s name on the frame; a beer Koozie; a boxing glove key chain; and a $300 special-edition leather and wool letterman jacket. Collectors, devoted to every wave of memorabilia style, from the blocky graphics of the 1990s to the minimal modern versions, are at the ready.

This week’s show will be Eric Fellen’s 151st time seeing Mr. Joel in concert, and his 100th time seeing him perform during the residency alone.