@Kimi Party Majors Hi! Great questions, though I think you'll find some of them already answered in various other forum posts. Here's a link to all the posts that come up when you search the forums for "freezing dough": http://cookieconnection.juliau...agination.sort=SCORE
This post does a particularly good job of explaining the effects of freezing cookie dough on spreading (which can help with some recipes and not with others): http://cookieconnection.juliau...8#371155709058071478
But, briefly, to answer your question from my point of view:
(1) Depends on the recipe; some are more prone to perishing than others, like those with eggs and high in butter fat. And, depending on how well the dough is wrapped, it could dry out at different rates. I wouldn't use my recipe after more than 5 or so days. Even though I double-wrap it in plastic and then foil, it eventually dries out a little and picks up odors from the fridge.
(2) This is largely hogwash, IMO, if the idea behind the freezing is to diminish spread. If a recipe is well formulated to prevent spreading in the first place, freezing after cutting will have little effect on the dough spread. (I have a new gingerbread video on YouTube on this very topic.) If it isn't, then chilling can solidify butter fat, which can help to prevent spreading. So every recipe will respond to freezing differently. But, the primary reason I challenge this statement is: why take up valuable space in your freezer by cutting out shapes and then freezing them? When I want to make dough in advance for later use, I simply freeze the mass of dough; then roll off portions and bake to order as I need it. This saves a ton of freezer space, yet I still have the advantage of having made the dough in advance.
(3) Again, depends on the recipe and how you've packaged the cut dough. I freeze blobs of dough for up to three months, but it is tightly wrapped in plastic and then foil (and sometimes even bagged) to prevent freezer burn and drying.
(4) I don't understand this question. Frozen cookies would, of course, have to be baked before decorating. If you meant, "how long do you wait before decorating a frozen already-baked cookie?", then I'd also say "it depends". The cookies need to be completely thawed out and at room temperature, as the moisture from the thawing process could interfere with the setting of the icing and contribute to colors bleeding. Thawing time depends on the size of the cookie, ambient temperature, how the cookie are laid out (or not) to thaw, etc.
(5) Again, depends on the recipe; they all have different staling properties. I like to eat highly spiced doughs within a week of baking for maximum freshness and flavor; others can be pushed longer depending on your palate.
Sorry to sound vague, but, truly, much of the above depends on the recipe you use and ambient conditions, such as temperature and storage methods. I always advise people to look for sensory cues, especially when baking and thawing, rather than just exact times. Also, it's important to taste your particular cookie recipe over time to determine when you personally begin to sense a deterioration in flavor and texture. Nothing can determine this better than your own palate, as freshness is so subjective anyway.