I’m far from a habitual up-grader.
Re old MIDI instruments, I bought plug-in (VI) versions of some of my old (digital-based) hardware instruments, including the Yamaha DX7 & Korg T1. Within SX3, I was then able to run some of the old “.ARR” (Atari Cubase “arrangement”) files that had sent MIDI data to those hardware instruments. I was surprised how accurate the emulation was - and the sound quality was better (less noise, if nothing else) than my recordings of the old instruments. Using an Emu (VST) VI, I was also able to recreate old sequences that had used the Emu Proteus 2. It was satisfying to bring those old sequences back to life, and quite luxurious being able to get everything ready just by opening the SX3 project file, instead of first having to get the instruments and mixer (and reverb/effects) set up.
As for older, purely analogue (or, at least, pre-MIDI) instruments, I might one day try to recreate a few old synth-based tracks, if I can make VI synths and any associated FX to sound close enough - though that would probably be hard work: amongst other things, a lot of listening to the originals, to try to play the same notes again. I might just settle for improving the sound of the old recordings.
Concerning Cubase, I seem now to be settling into taking alternate updates. After a long gap from getting VST/32, I got C4 when it first came out, but was so horrified by defects in the initial release that I used SX3 instead until the final C4 version was available (when C5 came out). Then I decided to wait for C6 to be released, whereupon I intended to use the final C5 (on a C6 license) until C6 was “finished” (which it isn’t yet); but delays meant I eventually bought the C6 upgrade in December, to beat the price increase. Nothing installed yet, but I still expect to settle into mainly using C5 for some time, unless there’s somehing in C6 that I need.
I upgraded from Wavelab 3 to 6, when 6 came out. I might never upgrade to 7 - I rarely need to use WL, and I don’t like the idea of learning to use a radically different version of WL without a proper manual (even a pdf would do).
My over-20-yr-old Korg T1 is still my main MIDI keyboard (not for its sounds, though) and my somewhat older DX7 sits above it, ready for the not very frequent times when I need to play on two keyboards at once. I fell in love with the feel of the T1 keyboard when I first played one in a shop in London. The DX7 keyboard feels a little unpleasant, and it’s keys are slightly narrow - but I’ve got it so I use it.
I still had a role (occasionally) for my even older Roland MC202 until a couple of years ago when I tried to switch it on but it didn’t work.
Last year I bought a cheap, refurbished laptop (WXP, 2GB) to run a free version of Cubase, for making quick rough recordings of my piano, without having to turn on my main Cubase PC and trail mic cables to it. (I have another laptop, used perhaps once or twice a month (around the house), but it’s too old and puny for recording audio.)
I have a 12-year old PC that gets used just about every week (admin, invoices, storing scans of documents, etc - at one time it acted as my photocopier and fax machine as well). I hate setting up new PCs and transferring stuff to them from old PCs, so I just keep using the old one for those things.
My mobile phone is eight years old.