No, a landlord may not enter your unit without reasonable notice (usually 24-48 hours) unless there is an emergency inside the unit.
Emergencies are:
Read your lease thoroughly. Usually each state has a standard format. Almost all states provide for the landlord being able to enter your apartment. In every lease there should be a mention of how much notice the landlord must give the tenant prior to entering the apartment.
You should revisit your lease to determine whether you can sublet without the landlord's permission. Most of the time, you have to speak to the landlord before moving someone in your apartment or home.
He can't enter the apartment without permission. Once the tenant lets him in the apartment, I suppose he can go into any room, without asking. Surely the tenants have the right to tell him not to go into certain room. This might be a question of whether they did.
Yes and No. It really depends on whether or not changing this filter constituted an emergency situation. If it does not, the owner must technically obtain a lawyer and file to enter your apartment without your permission. However, if he has evidence of trying to reach you unsuccessfully, and nothing in your apartment was damaged or destroyed, a court is likely to rule in his favor if you took him to court. Think Properties NYC
I don't think that a real estate agency has any right to take pictures of an occupied apartment without that occupant's permission. If this happened to you then you could sue for damages. Of course there could be an exception to this rule if it's written in your lease. But in my opinion that would be considered unconscionable.
Yes. The landlord should give you at least 24 hours of notice to enter without your permission or have your permission. There may be local stipulations for the landlords, an example being that where I live, the landlord can show the apartment only in the month preceding the move out date.
Find a landlord who will allow you to rent without regard to your credit score. This will likely be a mom and pop landlord and not an apartment rental service, but you will be able to get a place and work on your credit.
No, not always. In cases of emergency (fire, major water leak), they may enter without delay. More generally, however, the landlord is required to give notice, e.g. 24 hours, and to enter during "normal business hours", e.g. 8AM-5PM. They would need permission otherwise but a tenant can't refuse a justifiable entry such as coming in for scheduled maintenance or showing the apartment when the tenant is leaving or being evicted.
No he is not allowed to enter your home without your permission (given that you are paying rent and have a contract). Unless he suspects something to be wrong. Like a fire, water leak and stuff of that nature (that can damage the property). Even if the landlord is entering to fix something that you have reported to be broken he has to set a date with you or give you notice for the day of the repair.
No.
Yes, a landlord can enter a tenants bedroom without permission during an inspection. However, in most lease contracts, they have to give the renter a 24-hour notice for inspection.
No, as a roommate, you cannot charge your roommate more for rent than what the landlord has set. The rent amount is determined by the landlord or the lease agreement, and it is not within your rights to charge a higher amount without the landlord's permission.