Using 'spy out' implies stealth, suggesting actions are done covertly without being noticed.

Stealth Required

'Spy out' often connotes a deliberate activity aimed at gathering specific information.

Information Gathering

The phrase is commonly used in military or espionage contexts.

'Spy out' isn't limited to what one can see; it encompasses all forms of careful observation or search.

The phrase implies a methodical investigation, often requiring patience and attention to detail.

Use 'spy out' when the goal is to uncover information that is not immediately apparent or is hidden.