Nodes are an essential part of the Monero network infrastructure. They store a copy of the blockchain, and they can be configured to share the data with other nodes and users as well. Running a node is the only way in which you can obtain the highest level of privacy and security when you are connecting to the Monero network. The software that uses a full node is called the daemon.
Running a full node will use about 30GB of storage, but this will increase over time. It will also require a decent amount of bandwidth. It will more than likely take a few days to sync the whole blockchain from scratch even if you have a fast hard drive and a fast connection. The amount of bandwidth used will vary based on the Internet speed and more settings. Monthly bandwidth use will practically require about 100 GB per month, and it can also reach several terabytes.
There are a lot of users who run the daemon from a terminal interface, and this usually happens when they are running a VPS. Users are also advised to do this is they want to stay in sync without having to keep the wallet open.
It’s important to note that if you are already running the official Monero GUI, it will ask you to run the daemon locally by default. This will be the same as running a full node. All you will have to do is to specify the daemon options in the “daemon startup flags” if you wish. The GUI should then start and stop the daemon process automatically.