CLARKONOMICS: New data on rental apartments shows that the number of vacancies is the highest its been in a generation. You'd have to go back to the mid-1980s to find a similar glut of empty rentals in the marketplace.

This is the complete opposite of what economists expected. Technically, the rash of foreclosures should have created more renters. But there were several factors running interference here.

For example, a large shadow market of condo owners who can't sell have become involuntary landlords. That creates competition for the traditional apartment complexes. Second, many people in their 20s are getting out of school and going straight back home to live with their families, or else they're boomeranging back home after living on their own once they face a job loss.

This means opportunity for you as a renter if you choose to seize it.

If you're looking to negotiate a lower rent, Clark recommends you start doing a thorough search of traditional apartments about 2 months before your current lease is up. You should also check out condos, which may be newer and may rent for less per square foot than an apartment.

Take the info you've collected and lay it out for your landlord or property manager. By showing them what's available in the marketplace, you have some ammunition to try asking for a better deal on rent. You may be surprised at the offer your landlord comes back with to keep you.

Remember, you have all the power if you choose to use it. The ultimate power is to be willing to pick up and move if your landlord won't offer you a better deal.

If you vacate an apartment, be sure to leave it spotless and make any necessary repairs. Hire a cleaner to get it in order if you must. Just be certain to take pictures or video of the condition so the landlord has no reason to withhold your security deposit.