10 years with this tube, and the day has finally come. RIP.
I have had this tube of MX4 since 2013, it's served me well, countless rebuilds of my computers, CPUs and GPUs alike, home servers, gaming computers, laptops, games consoles, pi4, I used this on everything. You served me well.
I didn't notice any breakdown of the paste. It typically dries out over time once applied, this was still the same consistency throughout its life (in the tube)
This has been my experience with MX-4 as well. It's really really really stable. I've never had to re-apply MX-4 due to it drying out, either. (It's supposed to last at least 8 years in use.)
The same tube has been sitting in my drawer and every time I've needed it, every few years, it's been good.
I have decade old tubes. Maybe some bits around the entrance can dry out if you didn't clean them after use but it doesn't seem to be an issue for mine as far as the inside stuff goes (of course I put the cap back on as well).
Idk the tube of arcticnaut I have came with a little wide applicator that I used to just kinda paint the whole thing in the thinnest layer possible with the coherence of the paste being what it is. Squished out a bit over the sides but didn't get around the socket or anything.
Idk what Thermal Grizzly Cryonaut comes with but dammit if it doesn't do the job. I've seen 70C on my CPU once and that was during a video render, a game has never broken that barrier. It's Ryzen Master Auto O/C'd so idk what it would be getting without that boost in performance.