[AHTERIX5000]

Or the display sleep menu which offers choices like 1, 2, 5, 10, 15 and 30 min timeout but no more than that unless you use external config editor.

[amlib]

30 minutes? That's a luxury! For me it has always been limited to 15 minutes in the GUI.

[lozf]

You can also use `gsettings set ...` on the CLI.

[CRConrad]

God forbid an input box in a GUI config dialog.