I never had to replace either, although I don't want them non replacable. External/cloud storage can take care of space, and memory corruption is a fear, but nothing I worry about, batteries are worst than both combined.
I don't think I ever had a single machine where I stayed with the storage it came with.
As for memory, DRAM doesn't really have a particularly long lifetime (iirc design life is something like 75k hours), and that certainly shows in servers - memory modules start to fail a lot after the four year mark. And here I don't think I ever had a machine where I didn't upgrade memory at least once.
Mine came with a 500GB SSD, the older one I had I swapped it since it came with an HDD. I never had computer ram ever fail me, ever in my lifetime, have you? Unless you bought it with low specs, it isn't useful is it? I'd add ram to low spec computers, but my current one came with one slot and 8GB, no change to it for me.
