I'm just starting to learn investing so maybe I'm a bit skeptical of the websites, courses, and gurus who show everything as easy and rosy. They never mention all the things that can go wrong. How do you calculate the costs of major problems, and what can be done to insure that I'm protected. For example, what if a major appliance like the A/C or boiler goes bad? Is insurance recommended for that? Where will the money come from? These guru's only show the successes and don't factor in potential calamities. What are potential problems, i.e. trashed by tenants, appliances gone bad, lawsuits etc.? What can go wrong and REALISTICALLY how much of a buffer should I allow myself for potential problems.