[2] Stay Gold introduced new elements to First Aid Kit's music, such as a 16-piece orchestra, arranged and orchestrated by Nathaniel Walcott.

The album received acclaim from many music critics, gaining an overall metacritic score of 80, indicating generally favorable reviews.

[4] Scott Kerr of AllMusic noted that the album is "noticeably more expansive than any of their previous work", and "has a rich texture of classic country instrumentation and stirring string arrangements, matching their soaring vocal melodies.

"[5] The music review site musicOMH complimented on the larger sound that came from the band utilising more instruments, as well as the sister's "new-found, beefed up timbres".

[6] Stephen M. Deusner of Pitchfork thought that the Söderbergs sisters "remain romantics in an unromantic world, not only writing lyrics about fighting the good fight but making the kind of wide-eyed, ‘70s-tinged folk-rock that thrives on soaring vocals, warm harmonies, big choruses, and heart-on-sleeve lyrics."

[11] Leonie Cooper of NME thought that the duo had mastered "the art of sophisticated sadness", and "carefully crafted a tender batch of songs that disarm not only with their beauty but also their honesty.

Randall Roberts of the Los Angeles Times found that "the group often sounds more derivative than it does inspired", not helped by its "clumsy lyrics".