Landlords will usually do inspections of the rental apartment or home either yearly or 2 times per year.
The landlord must also give the tenant 24 to 48 hours notice before they show up for the inspection.
When I was renting an apartment the landlord inspection only took between 20 minutes to 30 minutes at most.
The landlord should and has to give you between 24 hours to 48 hours of notice prior to the inspection.
Before the inspection make sure you clean the floors, vacuum, clean the shower, clean dust and do your dishes etc.
Make sure you have not done any damage to the apartment or rental house and everything will go smooth with the landlord inspection.
The landlord just wants to make sure you're keeping the place clean and tidy and have not done any damage to the apartment or home.
They also want to make sure everything is in good working condition and in case they need to fix something.