My first (and still favorite) guitar was/is a 1955 Martin 00018.   
A guy I was casually dating at the time (1960) was in a rock band and had just bought two guitars that were more suited to that kind of music.   I was eager to try folk music so I asked him if I could buy his "old guitar."   He said, "No, but you can have it." So he gave it to me, including an oversized wooden case.

The narrow neck and easy action made it an ideal guitar for me, but I had no idea what a great guitar I'd been given -- until people I met when playing it kept saying, "You have a MARTIN!!!???" and offering to buy it from me (usually for about $500.)

That guitar, along with the nickname he casually tossed at "her" when he have "her" to me, is still my treasure. She's pretty beat-up looking, having been my only guitar for decades and going to parties, the beach, picnics, etc., as well as travelling cross-country, but sounds better than ever.

I wished I aged as well as old Martins do. LOL

Genie