I'm a D-76 guy (and not just because I work for Kodak - and the opinion is my own not EKC's). I have only had it go bad on me one time in my life. That's why I stick with it.
I mix up a gallon and decant it immediately into four one-quart plastic bottles with fresh seals cut from the lids of Skippy peanut butter. The first three bottles are filled up to the top and I try to seal without letting any air in. The fourth bottle is a little shy. I just use it first.
These bottles last a long time in my opinion. Last batch mixed in April lasted until October. Sensitometer and densitometer show consistent times.
When I get into developing film, I'll make a couple runs and use up a bottle. It doesn't seem to hurt to leave a half-bottle around a week or two if I feel like stretching it out.
Sometimes I feel like switching to HC-110 because it is a concentrate you can mix up one-shot at any time.
I'm on a roll now... second bottle of the October batch is at 68-degrees so time to pour it in...