A landlord has a right to show your apartment at reasonable times, with advance notice to you -- but only if your lease or tenancy is coming to an end. If you have 6 months to go on your lease, he really should not be showing it. If you have no lease and can be evicted on 30 days notice, he has the right to show it. I hope this helps.
Lawyer
26 years litigating important insurance and injury cases; well-known legal author