Some stuff I learned:
Improvements
The costs of making improvements to a business asset are capital expenses if the improvements add to the value of the asset, appreciably lengthen the time you can use it, or adapt it to a different use. Improvements are generally major expenditures. Some examples are: new electric wiring, a new roof, a new floor, new plumbing, bricking up windows to strengthen a wall, and lighting improvements.
However, you can currently deduct repairs that keep your property in a normal efficient operating condition as a business expense. Treat as repairs amounts paid to replace parts of a machine that only keep it in a normal operating condition.
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From this I am guessing that a new roof or kitchen is sure a capital expendure, but fixing the fence or painting the wall is to keep it in normal operating condition so can be expensed.
Interesting part of pub 525 is the start-up cost which it says you can deduct up to 5k then captalize rest. But I am not quite sure what qualify as start-up cost. Rehabing a 白菜算不算？
http://www.irs.gov/publications/p535/ch07.html#d0e4499
