The issue is when you need to echo something as root/sudo, that it doesn't work. You can never do a sudo echo to an output file as you'd expect.
Take an example to clear out wasted RAM buffers/cache like this:
sudo echo 1 > /proc/sys/vm/drop_caches
-bash: /proc/sys/vm/drop_caches: Permission denied
What we do is echo 1, but then pipe it to the "tee" command as sudo, which then writes the value to the proc entry drop_caches.
echo 1|sudo tee /proc/sys/vm/drop_caches
This will of course work whenever you need to echo something that requires root privileges.