Deposit
The deposit, and getting it back
A German deposit is capped at three cold rents and you may pay it in three monthly instalments. Unpaid rent and real damage may be deducted, normal wear and tear may not. No statutory deadline exists for the refund; a few months is what courts consider reasonable, and the handover protocol settles almost every argument about it.
The cap, and your right to pay in parts
§ 551 BGB caps the deposit at three times the cold rent, calculated without the service-charge advance. A clause asking for more is void for the excess, and you can reclaim it.
You also have the right to pay in three equal monthly instalments, the first at the start of the tenancy. A contract clause demanding the full amount upfront does not override this; the right is statutory.
Furnished short-term lets commonly ask for two months, usually calculated on the all-inclusive price. Because there is no separate cold rent in those contracts, the arithmetic is different from an empty flat.
While you live there
The deposit stays untouched until the tenancy ends. It is a security, not a balance that current claims are taken from, and you will not see it again during the tenancy.
You also may not live it out, meaning you cannot simply skip the last month's rent. Doing so puts you in arrears, and the final statement then carries one more open claim than it otherwise would.
If the flat is sold while you live there, the deposit passes to the new owner along with the tenancy. From then on they, not the previous landlord, are who you ask for it back.
Deductions: the line between wear and damage
A landlord may deduct open claims from the tenancy: unpaid rent, a shortfall from the service-charge settlement, and compensation for genuine damage.
What may not be deducted is ordinary wear from normal use. § 538 BGB says so plainly, and it is the most common dispute: scuff marks on the floor, a reasonable number of picture hooks, walls dulled after years are wear, not damage. A burn in the parquet, a cracked basin, a missing door are damage.
Watch for clauses about Schönheitsreparaturen, cosmetic repairs. Many are void, especially rigid schedules that require redecorating on a timetable regardless of condition, and any obligation to redecorate at the end when the flat was handed over undecorated. Where the clause is void, you owe nothing and the deduction is unjustified.
How long they may take
There is no statutory deadline. The landlord may take a reasonable period to check for outstanding claims; in practice courts accept something in the range of three to six months, depending on whether a service-charge settlement is still pending.
If only that settlement is outstanding, they may hold back a proportionate amount, not the whole deposit. If months pass with no word, set a written deadline and demand a statement for whatever is being withheld.
Two practical things speed it up: sign a handover protocol recording the condition of the flat when you leave, and send your bank details without being asked. Most delays come down to the landlord not having an account number.