So I am not one of the best out there but will try to help if you are having any issues on your android phones.
Questions as well will be entertained as far as my knowledge goes.
Just a bit of giving back to this forums in which i learned a lot.

Just a few notions to clear as well.
Basics:

Rooting

not sure but most are already tech savy nowadays, but would like to run by it just in case someone is still in the dark.

What does it exactly do?

it just gives you administration level access to your phone nothing else. Yes it also voids warranty.

Rooting is useful and pretty much the basic step before you install major stuff on your phone and also major tweaks.
Rooting is useless without any supporting apps or customization.

with root plus the help of root uninstaller (found on the playstore)
you can more or less delete unnecessary apps from your phone,like the samsung store,and every other app on your phone,but keep in mind that the phone is made app of several apps,so deleting something you don't know exactly what is for my turn your phone unusable.


Recovery

its basically one of the back bones of your phone,similar to a bios on your pc,i think.
what it does,well on a factory based recovery,the one that came with the phone, can only help you in unlocking a locked phone,nothing else.

Custom recoveries can do as much as recover a whole system that was already backed up,and gives you privilage to install neat stuff on your phone,like the infamous beats audio that was "exclusive" on htc. even upgrade camera's pixel count,given that somebody already made it for your phone.

common custom roms are cwm and twrp

its basically your best friend.

ROMs and Custom Roms.

Now basically what you see on your phone is called a rom,the feel,gui and response is all dictated by your rom,similar to an os on the pc,


Custom roms
are basically suped up roms.
having various upgrades to what your current rom does not offer.
example,for a samsung note 1 phone.

a custom rom has been made to have an xperia feel to it,xperia interface and even throw in the bravia engine from sony,and beats from htc.



i hope this helps,if any info is outdated,feel free to comment.