In reflection of e-mail retention policies, I bring you this quote I kept from a long-ago Wired article:
"Thinking is based on selection and weeding out; remembering everything is strangely similar to forgetting everything. Maybe most things that people do shouldn't be remembered. Maybe forgetting is good." - Rob Jellinghaus, of the Xanadu Project
(Ironically, this quote would not have been retained by most email retention policies. :))
ssh+2FA to all your machines, anywhere, without opening firewall ports.