This isn't the 1990s.
- My various documents folders are all in my Dropbox folder, which gives me off-site replication that I can access via iphone or ipad or any of my other computers.
- My various email accounts are co-hosted various IMAP servers (eg gmail). If my computer dies, I can access / re-download access email from another computer or ipad or iphone.
- I finally broke down and paid for an iCloud subscription to back up my photos and video clips.
- My text messages / contacts / diary / notes / reminders etc are also backed up to iCloud.
Just about everything else (apps, films, games etc) can be re-downloaded from the internet as needed.
- If my computer were to vanish this instant, I'd shift over to another computer and continue uninterrupted.
- If any of these cloud services (IMAP email, Dropbox, iCloud Drive etc) were to vanish suddenly, I still have my local copy and can re-upload to a different cloud server.
Finally, I have a rather ancient Time Capsule that does local backups every hour. But I am becoming increasingly resigned to Apple's neglect of Time Machine / Time Capsule. It doesn't back up iOS devices, and it doesn't back up photos from these devices. Making a duplicate of the Time Capsule backup takes forever via the USB 2.0 port on it.