* update LE certs:
  * exec wildcard script in certbot.
  * exec mail script on host.
  * restart proxy.
  * update calendar event at LE cert expiration.

* rotate passwords:
  * desktop: root, user.
  * work: fs, root, user.
  * dasha: root.
  * home: root, backup.
  * phone: user.
  * pass: user.
  * laptop: fs, root, user.
  * external drives: backpack HDD + SSD, keys thumb drive.
  * Telegram: 2fa.

* backup:
  * copy backup drive to cold storage (home, desktop, dasha).
  * copy backup drive to external backup (backpack HDD + SSD, keys thumb drive).

* update:
  * system: home, desktop, work, dasha, laptop, vpn, fsight, phone, tablet, dashaphone.
  * apps: home, desktop, work, dasha, laptop, vpn, fsight, phone, tablet, dashaphone.
  * home: docker & nextcloud apps. 
  * router: firmware.
  * termux: phone, tablet.