I heard that memory prices going back up again!
There is some seriously dodgy market manipulation going on within the PC component industry.
If regulators took a serious look at it, there would be lots of companies & CEO's getting huge fines and going to prison.
Providing memory is cheap my advice is to buy more then you need early.
One reason for this is CPU's are not increasing in speed much that means a motherboard/CPU could be in use many years, plus if you populate the computer early you have the benefit of the extra memory for all those years.
Other reasons fitting high amounts of memory early, your memory will be matched and no issues matching memory years later. Another reason is you populate all the memory SIMMS (when there still clean) so you remove the problem of years later installing memory over SIMMS that potentially have dust/dirt over the contacts.
I think it depends where in the cycle you are, over time new standards come out so a big stack of RAM may not be that useful in years to come when you upgrade. For example I could have bought more DDR3 when it was cheap but then that would be wasted if I wanted to buy a DDR4 mobo. That said I do take your point that pace of change is a bit reduced these days, so the lifespan of memory is arguably increased a bit. I haven't upgraded my system since 2012, which would have seemed quite an alien idea to me 10 years ago when I was pretty much upgrading mobo and cpu every two years with memory/gfx card scattered inbetween as appropriate.
Regarding memory slots certainly in years gone by having all memory slots filled could lead to a reduction in stability of overclock.
I've not been monitoring the market for quite a while but I do recall being surprised how cheap DDR4 was when I looked a while back (as mentioned 32GB under £100 seemed pretty good).
Wow my 32GB cost me £110 in April, it's now £200.
So glad I bought it when I did.
Pretty overkill for my needs, but at least no chance of running out
Memory prices have more than double since Summer, forgot Brexit, these increases are way way higher.
We once sold 32GB kits at £79.99, they are all now closer and over £200.
so why has the price gone up so much?