Edited questions from Apartment Life, Sara Gebhardt's online discussion about rental issues.

QArlington: I live in an apartment with a roommate and our lease is about to run out. My roommate and I agreed to renew our lease for another year. We went to our rental office and asked about what we needed to do to renew. The leasing agent told us that we do not need to sign anything; we would just be renting month-to-month. Doesn't that sound strange? Does that mean we could move out without any notice? Can they raise our rent without notice or tell us we need to get out? I'm confused and not sure what to do. I am afraid I am going to get caught in a bad situation.

AIt looks as if your landlord is not offering you the chance to sign a year-long lease agreement. That means that you are automatically going month-to-month, which means you probably have to give 30 days' notice before moving out.

Your landlord also can give you 30 days' notice to move out and can raise your rent -- with notice, probably 30 days. Though you didn't sign anything, your last lease and its rules are basically rolled into the new month-to-month agreement. What it means is that your landlord is not committing to you for another full year for one reason or another.

Fairfax: My roommate and I just moved into a two-story (plus basement) townhouse that has central air conditioning. We closed most of the vents in the basement and first floor, but she insists that the second floor where our bedrooms are located is too hot. So she put in a window air-conditioning unit and has been running it in the evenings and into the night! I tried to explain that it isn't necessary with central air and will run up our electric bills, but she says that I am wrong and the window unit uses little electricity. We also have a picky landlord, and I don't think he would be happy to see the air conditioner in the bedroom. Am I being unreasonable?

No, you're not being unreasonable. A window air-conditioning unit uses a lot of energy. It is one of the big energy users out of major appliances. Running central air and a window unit is going to cause your bill to skyrocket. It's possible that the central air system isn't doing its job, so ask your landlord to have someone service it. Or, if that's not the case, ask your roommate to pay the majority of the electric bill while she uses the air conditioner.

Alexandria: I'm wondering if you can explain the logic behind pet rent. I was apartment hunting recently, and almost every apartment I visited had a pet rent, ranging from $10 to $30 per month, per pet. This is in addition to a nonrefundable pet fee ($250) and often a pet deposit as well. I can understand the pet fee, which I assume would take care of any necessary cleanup needed to be done after you move. And, okay, maybe I can also understand the additional pet deposit, which would cover any potential damages your pet might cause that the pet fee doesn't cover.

Every apartment I visited, I asked what that was for, and no one could give me a satisfactory answer. It seems to me that pet rents weren't around a few years ago when I was last apartment searching. (By the way, I have since applied to an apartment that had the lowest pet rent I could find.)

As I understand it, pet rent is a charge that goes to the continuous upkeep of an apartment community. Most likely, a bad pet -- perhaps an indoor/outdoor pet whose owner didn't clean up after it or a rambunctious dog that gets into the flower garden -- started the whole trend.

Sara Gebhardt's Apartment Life column appears biweekly in this section, and her Web chat appears monthly on www.washingtonpost.com.