Is there anything I should know or any steps that I should take before I upgrade? I haven't done it in years and just need to bite the bullet and do it.
I have a backup on my system on a external HDD and i pulled my harddrive for an SSD fairly recently.
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As others suggested in such cases (and I modestly did it as well), trying first the upgrade in a bootable clone drive of your entire system including all the software important to you, is the safer way.
Just accept that an external clone will not be as fast as your internal drive, which is normal.
Then work a bit with that upgraded clone and check for your feeling with it and for problems which might appear.
In my case a few applications did not work, meaning in some cases to have to spend money in newer versions or alternatives.
Some new applications or updates one must install in such cases are free or at least cheap, others however are expensive.
The suggestion you received to check posts for bugs in El Capitan won't help you though.
Every OS shows bugs and what counts for you are those affecting
your system and not those affecting others.
After reading many posts about problems in El Capitan everyone will soon discover that they are much dependent on the hardware and the software of those complaining. What works fine for some users causes problems to others and the opposite is also true.
Good luck!
Ed