Nothing, as long as it’s still running. You can use bots and channel peers to keep an eye on your node’s status.
Whenever my node goes offline I get two automated alerts and like four human ones.
Ain’t that right, nostr:npub1zdvj0favucg4y4aer9njge5hu3a2rkgtktat0r0scvx8jpqrgn2ss2f5ng?