Take care! (lit. Stay well for me)
'Stammi' — STAM-mi. Imperative of 'stare' + 'mi'. The 'mi' makes it personal — 'stay [well] for me'. Stress on the first syllable.
Use with close friends and family as a warm, affectionate farewell — especially after a good visit or when you won't see them for a while. Very personal and tender.
'Stammi bene' is the imperative of 'stare bene' (to be/stay well) + the indirect object pronoun 'mi' (for me). 'Stay well for me' — the 'mi' transforms the wellwish into a personal request. More intimate than 'stai bene'.
Stai bene!
Take care! / Be well!
Without 'mi' — slightly less intimate but equally warm. Standard among friends.
Abbi cura di te.
Take care of yourself.
More thoughtful — 'avere cura di sé' (to take care of oneself). Used when genuinely worried.
Prenditi cura.
Take care of yourself.
Short form of 'prenditi cura di te' — modern, slightly more casual
'Non sparire!' (don't disappear!) is a classic Italian way of asking someone to stay in touch. It reflects Italian anxiety about losing contact — friends who 'spariscono' (vanish) after a good friendship are a real social concern. Italians maintain relationships actively.