If its new and haven't killed the battery a ton, also if it doesn't freeze or get to cold it'll last weeks. Mine had 80% after a week doing 2 messages a day turning off inbetween
If you combine it before and put it into a bag or vacuum seal it combined I find its super messy. I usually bring those single size packs of honey/peanut butter or premix it into a squeeze tube before my hunt. This way you can assemble it there and eat it without it being as messy.
I split my peak meals up into two zip lock bags inside the original peak meal bag. I had a full peak meal once and it was to much food. This way you can still use the bag to heat your meal up in and it seems to help stop getting holes in them. I would like to try those mylar bags though.