what is considered reasonable wear and tear in MD? what is the time limit for them to give me a list of damages and my security back?

First, you need to consult your lease for guidance. Wear and tear is kinda subjective to the extent that if you are in a place a short time, it should be about the way you got it but if you are there longer, there is evidence in terms of carpet and appliance usage because it has been used. Consult an attorney to evaluate your lease and explain in MD if you cannot figure it out from your lease.