For me, the component change was my room. I was running and enjoying Maggie 1.7s but I knew speakers well out into the room wouldn't cut it if our next retirement house didn't offer a dedicated listening room so I needed to find my retirement speakers. Talk about a change of focus.
JansZen came to the rescue with his Valentina hybrid ESLs. This was a big jump up in cost and quality, but removed all the room limitations. I have since changed out nearly every other component. Linear Tube Audio's ZOTL40 amp and MZ2 preamp proved to be the best match for the new speakers. The amp/preamp swap created the need for a new phono stage. Don Sachs' custom phono stage now sits on the rack. The last change was planned to align with retirement; my last turntable, the Technics SL-1200G. All set now but needing to consider the room changed everything.
PS - my new house did give me a new and slightly bigger listening room, but I don't mind all the changes. My new system is way better. Room treatments and full cable upgrades were the finishing touches.