But using fixer one shot is such a waste. Now, I know that I am not overly experienced and even then I probably could get more life out of the fixer, but if you store carefully, clip test each time you use it, you should get much more life, even un-replenished. As a safe reference point, just download and read the data sheet for the rapid fixer. If you stick to the recommendations, you can't go wrong (you will find, though, that the shelf life will probably be longer!)