Worries about upgrading my OS

I'm not sure if CCC allows restoring to previous backups (the ones that are older than the current one), if yes, then that's good, if no, then get a Time Machine backup because it can do that.

Generally, I'd say that you should upgrade because you'll get much more compatibility for a longer period of time, and El Capitan has proven to be a very stable OS from my, and others' experience. There's Sierra coming out in a few months but I guess that it's not going to be as stable and it's not that necessary.

However, if you're actually planning to get a new computer in the next months and you don't need to upgrade, there's really no point in doing that. Apple's apparently planning to release a new redesign of the MBP this year maybe, so you may want to wait for that.

 

Why not update to El Capitan on a different drive, then boot from that to see if all performs well? Then if it's no good for you, just revert to using your internal.

 

If you don't need a MBP and you're just unsure whether you should upgrade, then definitely save a few thousand dollars and upgrade to El Capitan. There are actually very few problems with it today, much less than Yosemite and is probably one of the most stable OSes since Lion.

The thing is that if he has an external hard drive it'll be much slower than the internal SSD to begin with, which is already good enough of a reason as to why upgrade on the main storage.

 

I can't speak for #3, but:

1.) No. As long as you can run the installer provided by the MAS, you're good to go.

2.) From the few older machines I've updated to El Cap., it's taken an average of half an hour for the install itself. The installer itself is 6.21GB - you can figure out from that whether or not your plan can handle it.

4.) https://support.apple.com/en-us/HT201314 is how it's done these days. Internet recovery can reinstall the version of OS X that your Mac shipped with if you don't have backups etc, but it has to download it.

 

1) No, not at all. Zero product key or authentication required.

2) You have to download a 4.5 GB file. It should max take 30 minutes to install on your Mac. No more downloading after this.

3) Licenses will be transferred over. You don't need to re-authenticate. Keep in mind you need CCC 4.x or newer in order to work with El Cap.

4) Since Lion (mid 2011), all reinstallation is exclusively done through the recovery partition. Basically, when you got your computer, a separate partition on your hard drive (which is like probably 8 GB max) was made. If you boot into the recovery partition by holding Option on startup, you will access it. From there, you can erase the main drive, deal with other disk utility things, reinstall the OS, etc. When you will upgrade to El Capitan, this partition will be updated to reflect the new OS, that is, when you reinstall the OS, you will reinstall El Capitan. It's also important to note that if you boot into Internet Recovery by holding Command+Option+R at startup, you will have your system download the recovery partition (temporarily), which allows you to reinstall the original OS the computer came with, in case your drive gets corrupted or something. If you have a Time Machine backup, you can use either to restore back to an earlier version of OS X.

5) As I said, it's even simpler now because your CD is both on your drive and accessible on the cloud There's really nothing to worry about now.

 

El Capitan from the MAS is 6.21 GB, not 4.5 GB.

 

Oh whoops, my mistake I guess.

 

OP:
What follows is my advice and opinion only.

Whenever a new version of the OS is released, I "experiment" with it for a while, using an external drive, while my "current OS" remains running UNTOUCHED on my internal drive.

This way, I can "dual-boot" to the new copy of the OS, and see how it behaves with the apps I use, etc.

I suggest you do it this way.
Of course, you need an external drive of some sort.
ANY old drive will do. Even if it runs slower at the moment (than an internal, which might be an SSD), you can get an idea of how things are going to go...