New Personal "Best" for longest wait on a rejection letter

Three years and ten months.
Yep.
Story has been published and even republished in that time. This is why it is important not to sweat editorial guidelines so much and to just send stuff out. I wait eight months, which I regard as more than fair, and then send to the next market. I don't bother with queries anymore, unless it is to someone whom I've worked with or had personal contact with before. Because in my experience queries don't get answered in a timely fashion by certain markets. And every writer I know, myself included, has a story about a query that was answered "we don't have it" only to have a rejection or acceptance arrive from the same market some months later anyway.