[geoffjentry]

In Boston we have brokers but it's not this reason (EDIT: See end). The realtors are really only there as the front door to get the lease signed. The landlord does the rest of the landlording. The claim is that the value add the brokers provide is vetting potential tenants - credit checks, etc as well as the time investment of showing the unit.

The standard fee is 1 months rent and this is almost always paid by the tenant.

The arguments here tend to cluster into two groups: 1) Laws should be passed that the landlord needs to pay the realtor's fee and not the tenant. 2) It doesn't matter if #1 happens as the landlord would just bake it into the rent anyways.

EDIT: I should say it's not just this reason as what you cite does happen. But it's just de rigueur here regardless of if you're renting the upstairs unit of a homeowner or going through a property management company.

[heliodor]

The difference is that if it's baked into the rent you would be free to move around more often. Instead, every move costs one month's rent.