DSL lines work best within a few miles of the telephone company's central office. The company that brings you DSL will try to sell you its own ISP services, but don't rush into anything. Get the names of other local DSL ISPs and shop around for the best deal. Hedge your bets. Get into the closet.
Many apartments run phone lines into a locked phone closet.
Make the necessary arrangements in advance to let the installation technician in. Install jacks for all trades. This will cost less in the long run.