Under the law, a lease may only allow the landlord to enter your apartment so that the landlord can:

• Inspect the apartment,
• Make repairs, or
• Show the apartment to prospective tenants, purchasers or mortgages.

If you have a lease and it states other reasons that your landlord can enter your apartment, that part of your lease is illegal. 

Arguably the landlord cannot enter your apartment unless

• they must make repairs or
• have a court order.

With or without a lease, you are required to allow your landlord reasonable access (by appointment if possible) for the purpose of making repairs to Sanitary Code violations.

Housing courts generally require landlords to give tenants at least 24 hours' notice before entering the tenant's apartment unless:

• There is an emergency, such as a water leak into another apartment

However there are times when 24 hours is not enough notice. If you work or have other scheduling problems, ask the landlord to give you at least 2 days' notice so that you can make arrangements to be in the apartment.

However, given that you will want the repairs made as soon as possible, it is always best to be cooperative in allowing access for making repairs.

The law also does not require you to give a landlord a key to your apartment.