What Equipment Remains In Your System Long Term?

Reading through the various discussion forums, I see that Audiogoners value the constituent pieces that make up their systems differently. For example, some may be fond of a powerful set of monoblock amps that up the cornerstone of their system for many years. They will go through many combinations of associated equipment while never contemplating changing their beloved amps. Others take the same approach with a favorite set of speakers. I usually build my system around my current speakers, though in recent years I have acquired a set of BEL 1001 amps that I feel will be around for a long time. What criteria do you use to decide what equipment remains a long term resident in your system?

Fernando