Dutch has two second-person singular pronouns: jij/je (informal) and u (formal). The choice signals social register and relationship. Jij/je is used: with friends (vrienden), family (familie), peers and colleagues of the same level, children (to children, always jij), and in most casual contexts. In the Netherlands, jij has become the default even in contexts where u was once standard — customer service, shops, and many businesses now use jij to customers.
U is used: with elderly people (bejaarden) who you do not know well, in formal correspondence (official letters, formal emails), with authority figures in formal settings (judge, doctor in first meeting, government official), in formal public communication (some government documents still use u), and when you are unsure and want to be safe. In Belgium (Flemish Dutch), u is used more broadly than in the Netherlands — Flemish culture maintains formality more consistently.
Practical guidance: in the Netherlands, when in doubt, follow the other person’s lead. If they use jij with you, use jij back. If they start with u, match u until invited to be more informal. The phrase Zeg maar jij tegen me (Just say jij to me) is an explicit invitation to drop the formal address — a sign of warming relationship. Getting this wrong rarely causes serious offence — Dutch people appreciate the attempt. But using jij with a very elderly person you have just met can feel slightly disrespectful, while using u with a young colleague can feel stiff and distant.