Dumb Formula Question

m+j

I just stopped breastfeeding last week and have slowly been introducing formula to LO, so bear with me because I'm new to this!  When I make LO a bottle of formula and he doesn't drink it within an hour (time limit specified on the back of the container), can I refrigerate it and give it to him later?  I'm a bit confused.  One set of directions says he must drink the formula within an hour of making it and another gives instructions for making an entire day's worth at a time and putting it in the fridge.  I nanny share with a mommy who has always formula fed her baby and she has instructed the nanny that the bottles are to be used within 2 hours or thrown out.  

So which is it--1 hour and toss, 2 hours and toss, refrigerate?