From what I gathered it's best if you want privacy to set yourself up as a node is that right?
Does the node have to be operating all the time if you set one up on your computer?
Can you just switch it on when you need to send/receive and then switch it back off easily?
Does it take up a lot of space of resources back and forth?
You don't have to have a node because the official site says
"running the official Monero GUI, it will prompt you to run the daemon locally by default. This is the same as running a full node."
Bit confused which way I should go? If Monero GUI alone will give me same same privacy as node then why bother with node?
You can get pretty good (almost certainly good enough) privacy without running a node, just using feather wallet (or another) and connecting to a node over tor.
If you do run your own node, you can just turn it on as necessary, but it might take significant time to sync depending on your CPU and Internet. Running your own node is best for privacy, and if you do leave it on it helps strengthen the network.