I echo Jerry's comments above.
Two bath fixing is good policy in the darkroom. If it helps, my fixing routine is described below:
First fixer I keep in a gallon sized bottle, full to the brim, Ilford Hypam 1+4 concentration. I pour out as much as I need in the 1st fixer tray and use that throughout my printing session. I usually only make one or two prints, in two or more copies per printing session. 8x10" or larger.
2nd fixer I mix fresh every time, also Ilford Hypam 1+4 concentration. I mix one liter for 12x16" or smaller trays, or 1.5 liter for 16x20" or bigger trays and use that throughout the printing session.
At the end of the printing session, I pour what's left of the 2nd fixer into the 1st fixer bottle, and then top that up to completely full again with 1st fixer, just to fill the bottle, (and store the remaining leftover 1st fixer for silver recovery before I discard it).
I fix one minute in each bath, always above 65 degrees Fahrenheit, with constant agitation. No less. No more. Then the print goes into the washer.
The dangerous underfixed prints are the ones that look fine at first, but start to degrade a couple of years into it. It's even worse if that is work that you sell or give to someone, because you lose credibility as a craftsman. That exact thing happened to me, and I had to go back and print a couple of prints and do it right, along with trying to convince the person that they really wanted a properly fixed print, and not their money back... It's easier to do it right the first time.