It’s also pretty clear that 16GB would probably be enough for me (most of the time), for now. But would it be the in the years ahead?
I appreciate the response. That said, I am at pains to point out that not everyone wants to trade in their computer every few years, but most replies assume that they will or that they want to.
How much is Apple going to offer me on trade-in for a specced-up M4 Mini in, say, 4-5 years? I doubt it will be a significant amount of money.
Because i definitely don’t want to go to any effort to sell it privately, I just can’t be bothered at all with all of that fuss.
I tend to keep a system long enough resale value is pretty much a non-issue, and I don't like hassling with wiping the drive, reinstalling the OS, haggling, etc..., so I understand.
Answering your first point, above, involves some guess work. I'll lay out a somewhat analogous situation that might hope. I bought an early '08 Mac Pro for around 4 grand, it was my main computer for many years. Eventually it got a bit slow and glitchy, so I got an iMac for home and used the Mac Pro at a place I stayed when on call for work to occupy my down time. Eventually, it went kaput.
B&H Photo & Video had a sale on 2017 12" MacBooks with 512 gig SSD and only 8 gig RAM, so I picked one up as a replacement for the Mac Pro (sounds crazy but worked fine). I didn't like the 8 gig RAM, but that was the only configuration offered at a good sale price, and I didn't want to invest a lot of money in an offsite downtime entertainer that wasn't my main system. Paired with a 27" display it did fine for years. I eventually retired, and now use it when I travel and having a built-in keyboard is convenient.
But performance got slower over time. What helps? Closing some app.s. Not leaving Safari open with multiple browser tab.s open. With very few app.s open, it still does okay. I'm guessing 16 gig RAM would be useful right now, but it's not upgradable.
At this point, Ventura is the last officially supported OS (and what I use), and security updates likely won't go much longer). It's not my primary system, so as a compact travel Mac that fits in a backpack pocket, it's okay.
I don't think you will notice any difference in routine use between 16 and 24 gig RAM on an M4 Mac Mini for years.
If you use the system many years, and software written for more powerful future systems gets more resource-intensive, your M4 will eventually bog down a bit; that's true with any personal computer. When that happens, extra RAM might make the difference in helping it run a bit longer with less slow down.
I can't give specifics. I don't know to what extent mainstream home user software written in 2031 will demand more CPU and RAM resources.
I, no guru/just a home user, think it boils down to this:
1.) 16 vs. 24 won't make a noticeable difference for years.
2.) It may do so late in your system's life. Not huge, but noticeable.
3.) I doubt 'wear and tear' on the SSD from swap file usage is likely to brick your system over its life, but no guarantees.
4.) Instead of thinking about what apple hypothetically 'should' charge for an extra 8 gig RAM, what they pay for it or what someone thinks its objective market value is, ask instead what you will get out of it. That's what you're paying for.
5.) Peace of mind counts for something. $200 For added contentment with a system you'll have 6-7+ years is not the worst investment.