I make up one gallon of developer and fixer in good quality plastic bottles that held apple juice. Then I place the 3.8 liters in 4 plastic 1-liter plain seltzer water bottles (3x1 liter + 1x0.8 liters). They are made of PET plastic which is an excellent oxygen barrier. You can use other soda bottles, but let them sit full of water and change the water occassionally over a day or two to remove any residual flavoring odor. It makes sense that bottles designed to keep carbonation gas in are also good for keeping air from permeating into your solutions. I always just rinse them good with water; any residual detergent can make fixer milky when you make it up.
These bottles are highty squeezable to elimate air in the headspace, they are thin-walled so you can adjust to the right temperature quickly in a water bath, clear shipping tape stays on good over a paper label for labeling and a Sharpie waterproof pen is good for labeling the cap, and they cost nothing. If they are clear, store them in the dark (I use a tote for chemical storage).
I have kept solutions for the time indicated by Kodak for storage in fully-stoppered bottles (6 months) with no problem. However, I have found that D76 stock will discolor (turn amber) and affect the bottle if I develop less than the full 4 rolls that a liter will develop and then not use the developer for about 4-5 weeks. I don't know if the developer is bad but I don't take a chance.
I also filter each solution prior to each use with a coffee filter to remove the slight amount of debris you'll see if you shake the clear bottles and observe under a light.