I nursed/pumped for 6 months, including for 4 months after I went back to work. One thing I noticed is that the guidlines are much shorter if the source is trying to sell you something. For example, if you look at Similac's or Medela's data, they tend to shorten it (5 hours room temp, 3 days in the fridge, etc.). Shortening the time to them means you buy more bags, more bottles, or more formula.
I would trust La Leche League's website, which also matched my Lactation Consultant's directions. My baby's caretakers and I used these with no incident.(http://www.llli.org/FAQ/milkstorage.html)
- at room temperature for up to 10 hours
- in a refrigerator for up to 8 days
- in a freezer compartment inside a refrigerator (variable temperature due to the door opening frequently) for up to 2 weeks
- in a freezer compartment with a separate door (variable temperature due to the door opening frequently) for up to 3 to 4 months.
- in a separate deep freeze for up to 6 months or longer
- If milk has been frozen and thawed, it can be refrigerated for up to 24 hours for later use. It should not be refrozen.
As far as thawing goes, at night I usually moved the 2 bags for the next day from the freezer to the fridge and then warmed the bottle with a warmer. If I didn't have the time and needed to go straight from fozen, I would just put the bag in a glass of warm water on the counter for about a half hour. Just long enough to become liquid, and then I would put the bottle in the bottle warmer.