I have a DIPA in secondary and wanted to know if you drink it or put it back after testing with a hydrometer. I was told it could contaminate the batch so I've have been drinking it.
All hydrometer samples are to be drank. Like someone above mentioned, these are the rewards your beer delivers to you for doing regular Hydrometer readings.
I think it's really cool to taste the beer as it ages. My oatmeal I tasted a week after starting to ferment and the hops were really pronounced and bitter. 4 weeks later they've mellowed out a lot and it tasted great going into bottles.