In the state of PA can a landlord refuse to let you see copies and estimates of bills that he is claiming need to be repaired

I am a NJ not PA attorney but I assume the rules are much the same. The Landlord can refuse, and you can tell him no $ without documents proving the loss. If he sues you for collection, he must show the court the documents. Most Landlords allocate the replacement cost against wear and tear some will try to get the whole amount, but in a lawsuit, the defendant can always claim they did not cause ten years of wear and tear. Assuming you have a lease with the landlord in writing, then the usual interpretation is that all tenants are fully responsible for the full rent. A L can make a deal to accept 2/3rds of the rent if the other tenants will testify as to the other tenant skipping out. Landlords usually do this verbally and not in writing which means it is your word against his in a court of law. If there is a rent lawsuit, the Landlord must make an effort to "mitigate" his damages that is try to get a replacement tenant to pay the rent rather than go after the other tenants for all the missing months.