Bathrooms and kitchens often tend to get dirty faster then the rest of the home. Again, if you choose your roommates carefully, these problems can be avoided through compromise. Compromise through communication is the key to a healthy environment. If smoking is an issue, ask roommates if they would mind confining their smoking to their rooms or to an outside area. If a roommate is consistently inebriated and that poses a potential distraction, talk with him or her to resolve the matter before moving in together.
Parties are a fun social medium and are a great advantage to living off campus.
However, as hosts, you and your roommates must act responsibly. Remember that neighbors may be intolerant of persistent partying. If friends drive to the party, make sure that no one drives home drunk. Find someone who is willing to drive or call a taxi service. Roommates' girlfriends or boyfriends often spend the night.