It won't hurt to do some book-keeping, then each month:

sort your inflows

sort your outflows

then see which categories are "deductable", or which you have the most control on.

同意fdr的观点, book-keeping，虽然可能会boring，但是各项进出record会一目了然，每周、每月summarize一下, and then do the comparison from last week and last month。

有的地方可以省，有的地方是省不下来的。。。