We have not allowed pets in the past, mostly because we have not had any problems finding tenants without pets (but a lot of pet owners asked anyway). We are about to have 3 units in duplexes available for December 1, which is a cold time of the year around here, and not as many prospects for tenants. So, if we allowed small pets (we have a current request from somebody with a Chihuahua), what would be the going rate for extra pet rent? How do you word it in your lease? Extra security deposit as well? For security deposit, I'd prefer to just raise that requirement rather than specify it's a pet damage deposit. 

*Of note: the new duplex I am buying that will be available for December has 100% new flooring, to include a lot of carpeting.