I'm gonna give away my age here and say, Aerith Gainsborough. It was the first costume I'd ever made from scratch (and my second ever), and I debuted it at Sakuracon 2003, back when her name was still unquestionably spelled "Aeris".
After that, I wore that original costume to Kumoricon 2003, Sakuracon 2004, and Sakuracon 2005. Then I created an Advent Children-style Version 2.0 that I wore to Sakuracon 2007, Tokyo Game Show 2008, Summer Comiket 2008, Summer Comiket 2009, Winter Comiket 2009, Kumoricon 2010, Animation On Display 2012, and a handful of local anime/cosplay festivals in the United States and Japan.
So, overall, I've cosplayed as Aeris/th over a dozen times, spanning nine delightful years.
![Grin ;D](https://www.kumoricon.org/forums/Smileys/default/grin.gif)
![](https://www.kumoricon.org/forums/proxy.php?request=http%3A%2F%2Flivedoor.blogimg.jp%2Fgofan%2Fimgs%2Fa%2Fa%2Faa2bd7a2.jpg&hash=9770c66aa13c49d87b710f91b1d4f0ea1a8c5ff8)