Bekhorot 30: Localized Wrong and Generalized Right

A new mishnah! A person who is suspected or known to not be careful about the laws of the shemitah year may or may not be careful about tithing, and likewise with regard to the rules of purity/impurity. But once one is suspect, that person can't judge or bear witness, at least with regard to that specific arena. Also, a focus on the "chaver," someone who is known to be careful in all areas of halakhah. Including details that are debated between Beit Hillel and Beit Shammai.