ob://QmRZXnJoPgmAqoAz5MVzKZRJ3uRH2qMCyPRNrUYrA52s21/store = that guy is safe to trade with. I traded SYS for BCH with him.
one person told me just to run OB 30 mins every two days. Not sure of the actual threshold of inactivy you can have.
Official OpenBazaar Blogs here. Feel free to discuss.