What is a criteria for investment prop to hedge against a crash

[Josiah Hrusch]

Good evening fellow investors. I am fairly new to real-estate investing and have never really experienced a crash. My partner and I have bought a cash flowing duplex as well as a sfh. I personally have sfh and a duplex in contract for my personal  portfolio. We both are working well paying w2 jobs and are gearing up to purchase another rental property. We are trying to re write our criteria to hedge against  a crash.  We also do not want to over buy in this market. Do any of the more experienced investors who have lived through a crash have any recommendations for a criteria that does well in a recession?