a. I heard Maulana Dhooma Saheb, who teaches Mishkaat and Tirmidhi Shareef in Madrasah Inaamiyah mentioning to me that two are such sins that they become perpetual. i.e untill you make tauba from them, you get the sin for it every moment. One is trailing your garment below the ankles and the second is triming your beard less than a fist (i.e not keeping the Shar'i length) [I believe it will apply to shaving as well, because that is haram according to all]