Wear and tear, tenant liability
Whether it's carpeting, wallpaper, toilets, etc., here's a fact: there's a specified service life for everything in the apartment. So that tenants know, too, how landlords deal with this issue, there are service life tables. These establish the basis when it comes time to estimate signs of wear and tear.
Normal wear consists of changes which arise during normal, careful use. These include, e.g., yellowing wallpaper, traces of wear on walls and floors, etc. As long as these effects fall within the scope of the service life tables, they are calculated into the rent.
The tenant is liable for damage which does not fall within the scope of normal wear as set down in the service life tables. This consists of damage as a result of abnormal use which the tenant caused himself during his term of tenancy or is attributable to other people living there, guests or pets.
Scope of liability
For damage due to abnormal wear, the tenant generally pays for the repairs or any possible reduction in value, not the purchase of an expensive replacement. For replacement purchases, you pay only within the scope of the remaining service life. For example, if 5-year old wall-to-wall carpet must be replaced by the tenant due to abnormal wear, the tenant pays only 50% the cost of the new carpet because a wall-to-wall carpet of average quality has a maximum service life of 10 years.
Settlement through security deposit
Defects which must be paid for by the tenant can be deducted from his security deposit if the tenant specifically accepts this method. If the tenant does not agree, the landlord must seek legal recourse.
Attention: If the landlord does not make any legal claim (either through debt-collection proceedings or through a legal process) within a year after the rental relationship has ended, the tenant can demand that the bank return the security deposit.