[2] The lyrics tell the perspective of a man recollecting key life moments from ages 15 to 99, including romance, fatherhood, and midlife crisis.

[3] In a 2004 interview with VH1, Ondrasik summarized the message he wanted to convey in "100 Years": "You can't enjoy every moment.

[5]People magazine praised "100 Years" as a "poignant piano-based tune" with a "well-crafted message", in a review rating The Battle for Everything 3.5 out of four stars.

[6] For Billboard, Chuck Taylor commented: "The innate vulnerability of Ondrasik's voice ideally suits the message, making this among the most intelligent, poignant songs of the year.

"[7] Elysa Gardner of USA Today noticed "self-conscious sensitivity and bleating tenor" by Five for Fighting in "100 Years" and some other tracks on The Battle for Everything.

[8] Todd Goldstein of PopMatters had a more mixed review, calling the song "catchy" but criticizing the lyrical themes as "obvious, painfully overdone".