Generally, you keep a homeowner/landlord policy on your property and suggest that they get renter/tenant policy. You must ensure that your homeowner policy covers renting your property. The renter/tenant policy generally covers their liability, but not your property. For example, if there is a fire and it's caused by wiring in the house, your policy covers it. If it's caused by your tenants then your insurance goes after their liability, but if they aren't insured, you are still covered for the loss.

It depends on the landlord/property manager. It is sometimes required. It's a good idea to have it anyway. It not only protects your personal property, but it covers liability. For example, you have a dog and the dog bites somebody and you're sued. You're on the hook for the damages, not your landlord. No, landlords really can't cover you since they have no insurable interest in your personal property. In most places, that isn't even possible because of that. Landlord's/property management companies have policies to cover the dwelling, but not the property of those renting from them. It is becoming more and more customary for leases to include a clause that requires renters to have insurance. Like I said, it's in your best interest anyway.

No, it is not customary. Nor is it a good idea. Any landlord who does it is leaving himself or herself open to a world of hurt. First, it's very difficult to write a legally binding contract involving another party, such as the renter's insurance company. Making your lease contingent on the renter having insurance would mean that the tenant could get out of the lease simply by dropping the insurance policy. Also, you have no way of enforcing the policy and making sure the coverage is sufficient. For all you know, your renter could drop the coverage the day after the lease is signed and you'd never be the wiser. You aren't in the same position as, say, a bank that issues a mortgage and insists that the mortgage holder insure the property. Second, a landlord has nothing to gain by requiring a tenant to purchase renter's insurance. It is sufficient to include a clause in the lease or rental agreement stating that the landlord's insurance does not cover the renter's belongings. Third, it would be a very bad idea to try to cover the tenant and charge them for it, unless the landlord is a licensed, registered insurance agent with the authority to write out a policy on behalf of an insurance company (or unless the landlord has the financial wherewithal to actually underwrite the renter and pay out on demand for a total loss). If the landlord really is an insurance agent, using the lease as a way to force the renter to buy his or her product introduces what's called a conflict of interest, and it also creates an element of coercion if buying the insurance is a condition of the rental agreement. Any contract that is coerced, or that contains a coercive element can potentially be thrown out if the coerced party (in this case the tenant) complains. Fourth, a landlord's insurance policy covers the landlord's property only. It's not possible to extend the coverage to third parties such as the renter, because extending the coverage to third parties would mean the insurer has no opportunity to weigh the risk, reject an unfit or dangerous renter, or calibrate the premiums based on what the renter owns. Loss-of-use or liability insurance is likewise for the landlord only. I'm not a lawyer or an insurance agent but I've been a landlord for years and managed my own properties.