These are my own opinions. Many do not agree with them.
I think everyone should have her own personal, permanent email address.
By permanent, I mean not dependent on employer, residence, ISP, or computer operating system.
Any of these can change, sometimes suddenly.
By personal, I mean not shared with another person. I find his and her addresses unnecessarily confusing.
By everyone, I mean, well, everyone, even those too old or young, or otherwise unable or unwilling to use a computer.
Something like Gmail is probably the easiest solution for most folks.
It is also much more likely to survive a computer disaster. Some will prefer the additional control provided by having their own domain names.
This does not mean one should not have other addresses. For example, Jane could have
firstname.lastname@example.org as well as
Jane74@mycurrentisp.net, (try not to use this one, centurylink seems especially bad)
Treasurer@myclub.org, and even
Most of these accounts would be forwarded to her work and/or home accounts.
She could also have mail forwarded from email@example.com.