On Tue, 15 Apr 2014 22:16:21 -0700, Danny D. wrote:

Here's a much more detailed summary, of a "typical" user setup:
http://farm3.staticflickr.com/2866/1...05818cf3_h.jpg

FINAL UPDATE:

The 12GB Nexus 5 phone has been given to the gift recipient:
https://farm3.staticflickr.com/2908/...d7300024_b.jpg

The suggested set of "typical" apps used about 2GB, in toto:
https://farm8.staticflickr.com/7269/...8cbce7b3_b.jpg

This included the suggested social-networking sites that I,
myself, would never consider, & it included the suggested games:
https://farm4.staticflickr.com/3684/...9b798401_b.jpg

Note that I didn't have access to any user content, so there
is as yet, no SIM card, nor any accounts which would need to be
logged into, so, the memory requirement can only grow from there.

Given this "typical" setup, it looks like we now know that the
bare minimum need for a decent Android phone to store apps in
primary memory seems to be roughly about 6G, comprising about
4GB for the pre-installed apps, plus a bare minimum of at least
2GB for a reasonably well vetted set of the suggested basic apps.

While, for complicated business reasons, the SD cards have proven
themselves useless for primary app storage, the SD card should
be "mostly" available for secondary storage of user content
(of which this phone had none).

Thanks for all your help and advice!

NOTE: The list of "typical" apps and their sizes has already
been posted to a separate thread, so it isn't repeated here.