In the commercial world removed fuel was considered waste only because the risk of litigation returning on the fuel company should it prove faulty was deemed too great. Whilst I have no issue with that where public transport is concerned for GA purposes I take a more pragmatic view.
I was brought up to throw the fuel away in an arc, and always did so until doing a check out with a school in Florida. The instructor looked at me aghast and said that apart from the fact that the fuel was perfectly useable before it came out, and given that the little plastic tube I'd just put it into was kept in a wrapper in the aircraft at all times, it was probably safe enough to put it back in. The cost to the school of doing it every flight would be more than noticeable on an annual basis. I duly complied. However it was his next comment that stayed with me.
"Before you throw that fuel away, just remember it might be the last drop that gets you to the field, or to the coast line in the event of you needing every gallon on board".
Seemed like sound advice and whilst I always drain my own aircraft if it's has been standing with partial tanks for more than 24 hours. If it looks okay it goes back in.