关于保存收据，提上来再说， 兼谢 SunshineCA mm.

看楼下的帖子提起file receipts， 想起来以前SunshineCA mm 推荐用 digital camera saving and filing all receipts electronically。

非常有用的suggestion. 我现在更进一步， 用iPhone.  Any time after buying anything from store like HD, just spend 5 second taking a picture of the receipt, then put the hard copy in big envelope. At the end of each month, move all picture to a folder for permanent record.

I have been using this for a month, and it worked like a charm.  Never need to worry about losing another receipt.

And If i need to return something, no need to looking for the receipts in the wallet, just show the clerk the picture from your iPhone.