https://www.irs.gov/businesses/small-businesses-self-employed/tangible-property-final-regulations
Step 1 – What is the unit of property to which you should apply the improvement rules?
For the Year Placed in Service - This rule, only for non-building property, is triggered at the time you initially placed the unit of property into service. If at the time the unit of property is first placed in service, you properly treat the component of the unit of property as being within a different MACRS class than the MACRS class for the unit of property of which the component is a part, or you properly depreciate the component using a different depreciation method than the depreciation method used for the unit of property of which the component is a part, then you must treat the component as a separate unit of property.
假如你建新房，你想把新房里面的空调机器算de minimus safe harbor，那么你必须把这个空调单独折旧，而不是算到新房里面按照27.5 年折旧。
这个就和你说得cost segregation有关了。民居房例子不太好，但是比如说旅馆每个房间都有一个小冰箱和微波炉。如果你买来的旅馆，可以把几十个上百个冰箱和微波炉单独折旧，这个叫做cost segregation。我还是从你那里听来的。
那么，你盖新旅馆，买来几十个上百个冰箱和微波炉安到房间里面，能不能按照de minimus safe harbor处理呢？为什么不可以？似乎是可以的啊？ （de minimus 有没有总值的限制？好像没有啊）
