Neil Thrasher and Jimmy Yeary explained to The Boot
that much of the song's inspiration came from their wives - Lana Thrasher and Sonya Isaacs-Yeary (of The Isaacs):
Yeary: I showed up to a writing appointment with Tom Shapiro, and I didn't have an idea that day. Right before I walked in Tom's office, I got a text message saying he had to run by the studio to close a mix and he was going to be about 40 minutes late. I was like, 'Phew, I've got time to come up with something.' What I like to do is turn on my digital recorder and whatever happens I'll get on tape – maybe it's something magical. I still have the recording of the melody to 'Why Wait.' In my head, I just thought up that opening lick. Tom came in from closing the mix, and he loved it. He thought it would make a tremendous Flatts song. He told me he was writing with Neil the next day. He presented it to Neil, and Neil loved it. We got together the following Friday to write it.
Thrasher: We were at Tom's office. We all got together, and we started talking like we always do before we write. It all initiated really from Jimmy – the melody and the feel. Jimmy came up with the opening signature guitar lick. It was really good. He was humming this melody over it.
Yeary: Sonya and I were newly married, so all I could talk about was that. I had just completely told our story about us deciding to get married after dating for only three months. Then Neil told me about how him and his wife had gotten married quickly.
Thrasher: Lana and I actually eloped. We are always pulling from that experience when we write, and we did again with this song, especially.
Yeary: We decided to write 'Why Wait' because it was certainly something we both could relate to since we both got married so quickly. After we finished the song, it got demoed a week later. We knew the Flatts were going in the studio soon. Sonya and I went on a Caribbean cruise. We had no cell service for a couple of days. I knew they were cutting songs, and I had no way of calling anybody back home to find out if I had gotten this Rascal Flatts cut. We finally dock, and we get some phone service. I called, and my publisher said, 'Congratulations on your Rascal Flatts cut.' I'm hootin' and hollerin', and Sonya hears me and starts hootin' and hollerin'. It was an incredible moment.