In a “breadbox” (such as you apparently have), up to a week, depending on ambient humidity. And without rescusitating. Problem is, without refrigeration, the ambient fungus spores that inevitably get in every time the package is opened have a chance to start growing. The spores don’t have that much chance to grow when the bread is in the fridge. OTOH, there’s minimal effect on taste when the bread is kept in a breadbox.
AAMOF, humidity is the key to each of the three questions. The reason why bread becomes progressively inedible in both fridge and freezer relates to the cooling process. The compressor that cools each/both of them removes humidity as it cools. What happens to the bread is that it becomes progressively drier, top to bottom (which side is up is “top” for this purpose). You can, if you remember to turn the loaf over every few days, keep bread for several weeks in the fridge, several months in the freezer. Of course, the more selective palate will taste the difference between bread that’s been refrigerated/frozen and that which hasn’t.
However, you need to realize that, even with “maintenance”, the bread dries out, and eventually is good for nothing (in the kitchen, that is) except bread crumbs or croutons.
You can somewhat revive bread which has been (evenly) dried in the fridge or freezer by sprinkling water over it, then heating it (in oven or microwave) in a paper bag, briefly. It’s been too long since I did any of this for me to give you accurate times. I’d start with 10 seconds per quarter loaf in the microwave, 10 minutes in a “slow” (~250) degF oven.
I, too, can keep bread fresh and edible for up to a month in the fridge.
I keep it in its original plastic wrapping to prevent the previously mentioned dehydration. If the bread was originally not in a plastic container (french bread or pizza, e.g.), I put it in an airtight plastic container.
I steam bread to moisten it if it has dried out. I also steam bread simply to warm it up (such as soft taco or gyro shells). If you don’t have a steamer, put a little water (hot, to reduce heating time) into your largest sauce pan (or even largest fry pan). Then place a metal colander (the bowl with the holes to drain spaghetti) in it. Once boiling, place the bread in the colander. It will be warmed in less than half a minute. You may want to turn it over. You also may want to shake it like a polaroid if it gets to soggy – it will dry quickly. Two things to note: 1. Steam is hotter than boiling water. Use an oven mitt or tongs to retrieve the bread (or take out the colander and dump the bread out); 2. You really aren’t supposed to shake a polaroid to develop it.
Other methods to moisten dried bread: Wrap dried-out bread in a damp paper towel and microwave it (which, in effect, is equivalent to steaming it). Note that over heating bread in the microwave will make it inedible – simply warming bread in the micro is the best you can do.
Another way to moisten bread (and dried out brownies or cookies) is by creating your own humid humidor. Place the bread/brownies/cookies in a sealed container with a water source (dish of water, clean sponge, damp paper towels). Within a few hours, the container will reach nearly 100% humidity and the bread product will absorb moisture rather than evaporate moisture. In half a day, all will be rejuvenated. However, don’t let this continue indefinitely. Such an environment will accelerate the growth of mold.