There's old addresses in my GUI wallet that were used for sending, receiving, are over a year old, wont ever be used again and I cant see how to delete them from the GUI. Should I keep them? I don't need them anymore so I tried to figure out how to delete them from the GUI and I assumed at that point they'd be gone from my laptop, etc, forever?
You can delete the wallet files directly if you don't want to see them. On linux they are in ~/Monero/wallets/ (linux).