Multiple issues including booting problem, seemingly broken file and fatal library error

ldconfig: File /usr/lib/ is empty, not checked. as mentioned above as well during updates…

Can you please explain what this means ?

Luckily I was able to solve all of my issues with a command I found on the reddit that told me to reinstall all of my files again.

pacman -Syu $(pacman -Qnq)

I tweaked this command. I was unable to overwrite the existing file for some reason so I used.

pacman -Syu $(pacman -Qnq) --overwrite "*"

and this fixed all of my issues but I would like to know what I ran across…

Also I would like to know from you guys what is a good update habit ?
When to update and when not to ?
Next time I update what things should I care about ?