Landlord won't return my deposit

Know the rules, then escalate in writing:

1. Some waiting is legal: landlords may hold the deposit for a reasonable review period — commonly up to ~6 months, and a portion longer if a utility reconciliation (Nebenkostenabrechnung) is genuinely pending. Total silence past that point is not normal.
2. Demand in writing: a short letter/email — move-out date, handover protocol reference, IBAN, and a 2-week deadline (Fristsetzung). Keep proof of sending.
3. Challenge vague deductions: normal wear and tear (Abnutzung) is the landlord's cost, not yours. Deductions need itemisation and, on request, receipts. Your signed handover protocol and photos are your ammunition — this is why the moving-out step insists on them.
4. Still nothing? The local Mieterverein (tenants' association) handles exactly this for its members, or a lawyer's letter (often covered if you have legal insurance). Small-claims court (Mahnverfahren) is cheap and effective for clear cases.
5. Moving abroad? Do all of this before leaving — chasing a deposit from another country is possible but grim.