If you rent your property out long enough, the odds are that you will eventually come across a demanding renters. These are the tenants that cannot be pleased, no matter how hard you try, and they often make unreasonable demands that will take away from your other duties.
While state laws may differ in exactly what this means, each will have a minimum requirement that the landlord must keep the property that they are renting out habitable for the tenant. Make sure you know your local laws and know if they detail out exactly what repairs have to be made and all the details attached to that. This will help you balance a demanding tenant. If a request is made that does not affect the habitability of the unit, you may remind them that it may take a bit longer to see to than something that does affect it.
Your lease should detail out your responsibilities to the tenant and to repairs that need to be made. The lease is a binding agreement between the two of you and when they sign their name to it, they are agreeing to the terms. This means that you need to live up to your responsibilities, but that they must also live up to theirs as detailed out in writing.
Don't let frustration take over when dealing with renters such as these. Professionalism is key, no matter how much they test your patience. It's best to get everything in writing so that there is a trail to document the communication.