How long can realtor go on showing my Apartment?

I live in a duplex building in Los Angeles. It has been up for sale perhaps a year now. Every now and then there is a posted note on my front door stating that the realtor will be showing the place for the umpteenth time! Does the owner, my landlady, have the right to inconvenience me and my roommate for as long as she wants ? This is truly infuriating !!