Two bath fixing has some advantages if you are doing a lot of printing. The method makes the most out of the fixer's capacity and assures adequate fixation throughout the session. You fix your prints for half the recommended time, with agitation, inthe first bath, then transfer them to the second bath for the remaining time. Most of the fixing happens in the first bath, which become loaded with silver complexes. After it is exhausted (Kodak says 200 8X10 prints per gallon, roughly 50 per liter), you discard the first bath, start start using the second bath as the first bath, and prepare a new second bath. Discard both baths after the equivalent of 1000 8X10 prints per gallon (250 per liter) have been fixed. If you only process 10 or 12 prints in a session and are not in the darkroom every day, the two bath method makes less sense. You would do better by mixing up a single fresh batch of fixer for each session.