Our DnD campaign has been going on for around 5 years already. It was supposed to be over years ago, but we just kept going. There has been numerous times when we have kinda concluded that it's time to retire our characters and move over to the next campaign.
Yet, here we still are, playing the same campaign. Except soon it's (supposed to) finally come to an end. Our DM told us there would be only a few more sessions when the story is finally over and it's time to move into a new campaign he has been planning for quite some time already.
I don't mind that it has been so long lived. I've grown to like my character, and our party. We've come a long way together. But playing the same game for so long has it's downsides as well. The level progression has been maybe a bit too fast to keep going any longer. We have already been at the max levels for a while. We have also accumulated quite a fortune and a nice selection of magical items. So there is no real challenge for us anymore no matter what we encounter.