What's the longest you've spent camping an item only to leave empty handed?

[Swish]

People might laugh but I spent a long time on live continually clearing the stables in CoM trying to get the courier to spawn for the shaman epic. He was way way rarer on live but I never looked for the evidence to support it to get it altered here (many thankful shammies I'm sure).

Got him on the second session but logged out empty handed after 8ish hours the first time.