What's the best backup practice?
 

I've done a full backup (all files) to an external drive. Now it's time to do another backup. I'm trying to figure out what the best practice is in choosing between "smart update", "copy newer" and "copy different". I've read through the documentation and think I understand the differences between these but yet remain unsure of what the best thing to do is. I'm just a regular user with no special needs but I just want to make sure that if anything happens to my computer I can restore valuable files. It would be helpful to know for each of these 3 options, the key reasons why someone would want to use them. In other words. If you want to do a, b and c and care about x, y and z you would use "smart update". If you want to do .... you would use "copy newer" etc. Can anyone help? Thanks.
Kevin

Kevin --

You should, really, almost always want to use Smart Update. If you want to keep "old files" around for longer, I'd suggest a daily, weekly and monthly backup, each on its own volume (or even drive). That way, you'll be able to recover accidentally deleted files from a week or month ago, even if you've updated your backup since then.

Copy Newer/Different don't guarantee bootability, because they never remove files from the backup (though they do overwrite, depending on the attributes of the files, and the method you choose). They can be helpful in specific situations -- like when you want to keep adding files to a backup, never removing things -- but are usually only necessary when you want to copy a bunch of stuff to an existing volume without removing anything.

A daily backup with Smart Update should be pretty fast?

For a little archiving, between two clones with SuperDuper, I suggest iBackup (on another partition or drive)!

Yes, a daily backup with Smart Update should be quite fast -- depending, of course, on the speed of the source and destination volumes.