I have four - one 5504, two 5508, and one 5040 - all are lifetime. The three 5500s are my main units that I use daily. The other is my backup, and now, testing unit.
I have double cable box setups in two rooms so I can watch another show while I record on the replay.
I have to admit, I am freaking out a little since these units are a major part of my entertainment life, not just because of the interface and obvious features we all now, but for the features you cannot get ANYWHERE else, such as actually streaming shows all over the place, using the extra large buffering capability so I can watch something hours later without having to record at all. And DVArchive makes it easy to download on occasion so I can keep video that you cannot even buy if you wanted to.
I am ready to call D&M can ask if there is a way to buy them out. Maybe we could form a co-op.