The tenant can call fair housing and withhold rent based on the property not being safe-mice carry germs.

The kind of tenant who 1. allows another to occupy without permission, 2. is dishonest (or at least withholding) about his occupancy, and 3. allows him to smoke inside - probably not the best in the long-term.

If you tried to withhold the deposit the tenant may decide to press their case in course and you would most likely have a difficult time convincing a judge that these issues are the tenants responsibility... especially since you don't have evidence of the condition before move in.Anytime I am purchasing a property where I am inheriting tenants I always assume that I will be returning the entire deposit to the tenant and I build that into my numbers.

If she asks for an outside hose bib, do NOT do so, unless it's in the lease that you will provide this.If she threatens to withhold rent because you haven't done what she is demanding, don't respond. 

Tenants usually have the legal right to withhold rent for the time they dont have essential services.     

If the landlord fails to send you a list of damages, they forfeit the right to withhold the security deposit.The security deposit, plus interest, less any damages rightfully withheld, must be returned within 45 days of your notice."

Tenants are catching wind of the "free pass" and beginning to withhold despite bolstered unemployment benefits.

What about withholding a legal notice to me from CE for three days? 

I liked their camaraderie, what more can I expect as landlord than having happy tenants around.One of the tenants left recently messed up few things as well as broke the lease terms so I had to withhold partial deposit and explained them why I had to withhold but the tenant left unhappy and not convinced.My current tenant who was friends with my previous tenant is pissed off with me,anyone ran into this situation?

A withholding of construction money, a collection of an interest payment at closing, all of these things count against the usury rate.