It used to be more common in the past: you buy something, and the fapiao (certified tax receipt) would include some sort of scratch off thing that was like a lottery; so you had some incentive to collect your fapiao and preventing the department store from low balling their taxes.

Store owners are not supposed to recycle unclaimed fapiaos, that is definitely illegal, and many companies who follow the law to the letter (like Starbucks) make it very convenient for you to exchange your xiaopiaos (normal receipts) for one fat fapiao in bulk, since they are not gaining anything by not issuing a fapiao.

Likewise, Microsoft (my employer, an American company) doesn't require us to play the fapiao game for most of our benefits. However, we need fapiaos for any expenses that occur in China, while there are a few benefits that require fapiaos (a travel and gym benefit) that are easy to get and one foreigner-only benefit where we can get back our tax on rent if only we could ever get our landlord to issue a fapiao (unlikely, they would just jack up the rent for the taxes they weren't dodging).

And let's not get started on getting the name right for the fapiao. It must be in Chinese and it must be the official name of our company. I think for Microsoft China its something like Microsoft (China) Limited, but all in Chinese characters, and its bad if you can't write that down exactly right.

[Edit] Let me describe the fapiao game: your company (usually a Chinese one) low balls your salary (say 2 or 3K RMB a month) but allows you to claim lots of personal expensive as business expenses. Even more fun: some require you to collect fapiaos but don't reimburse you for your expenses (universities do this a lot!). Fapiaos now require the name of the company that will be claiming the tax benefit so you can't just exchange them with your friends, meaning you need to be diligent about collecting fapiaos. Taxi fapiaos are the easiest, as they don't require names (so you can collect them and exchange them with friends if you want).