Wear and tear is the owner’s cost, always
Worn carpet, tired paint, a kitchen at the end of its life: none of that is an insured loss and none of it is properly a deduction from a deposit either. It is the cost of owning a property that people live in, and it should be budgeted rather than insured or argued about.
Sudden damage is a different question
A broken door, a hole in a wall, a deliberately damaged fitting may fall under vandalism or malicious damage depending on the form. Some landlord policies include it, some exclude tenant acts specifically. Knowing which you hold is worth more than the deposit itself.
Condition reports decide these arguments
A dated photographic record at the start and end of each tenancy settles nearly every dispute about what changed and when. Without one both the deposit discussion and any claim become a matter of competing recollection.