When is the best time to freeze bread?

In the book Advanced Bread and Pastry, Michael Suas outlines three methods that he recommends to professional bakers (but also applicable at home) for freezing bread at various stages, roughly in decreasing order of quality:

• Par-baked process. The bread or rolls are prepared normally and baked normally, but for a shorter amount of time (just until the structure is set). For best results, Suas recommends a relatively high temperature at first to maximize oven spring, then decrease to a much lower oven for the rest of the baking time. Bread should be pulled from the oven before most substantial browning, with just the basic structure intact so the bread doesn't collapse. Loaves or rolls are cooled to about room temperature and then frozen quickly. They may then be removed directly from the freezer and baked immediately, usually at a relatively high temperature. The biggest challenge for a home baker here is potential moisture loss and slight staling during cooling and freezing (as commercial bakeries tend to use a blast chiller). But if done well, the results are basically the same as normally baked bread.
• Frozen dough process. The dough is mixed/kneaded, divided, shaped, and frozen immediately to minimize fermentation and gas activity. Generally the only modifications are to use cold ingredients and to mix/knead more thoroughly, as the lack of a shaping step after defrosting means that the the gluten must be thoroughly developed during the initial mix. High-gluten flour or added gluten may also help with the final rise. (Gas production and fermentation is then limited to avoid more damage to the gluten structure during the freezing process. It also makes it easier to wrap the dough tightly without much dough expansion during the freezing process.) When frozen dough is to be held longer, a higher yeast content may be used as the yeast activity will gradually die off with prolonged freezing. The best thawing method is slow and in the fridge. This also allows the possibility of reshaping (if necessary) before the final proof at room temperature. Final quality is usually okay but lower than parbaked results, either due to insufficient yeast activity/dough structure after freezing or excessive "yeasty" flavor if more yeast is added to the inital mix offset this. This method is usually best for enriched doughs that can distract from the lack of good flavor development.
• Preproof frozen process. Here the dough is mixed in the usual fashion, then shaped and allowed to undergo a single proof to about 75% of the usual final size. The dough is quickly frozen. It can then be removed from the freezer and placed directly in the oven to complete its rise and bake. This process is the most temperamental and least likely to produce bread of high quality. Suas only recommends this method be used for things like breakfast pastries with a high butter content -- to distract from poor flavor development and texture -- that will be consumed relatively quickly after baking. But it is very convenient to get a warm "fresh-baked" product quickly with little effort at the end. Still, Suas strongly recommends par-baking over this process for most baked goods. (And the frozen dough process at least allows the possibility for reshaping and controlling the final rise to get a better product.)

I've tried the first two processes myself at times, and they've both produced reasonably good results. Like the information I summarized above, I wouldn't recommend letting the dough rise before freezing though, unless you're going to parbake. More gas bubbles mean more ice crystals that will potentially damage the bread structure during freezing.

Other answers and comments have mentioned the possibility of doing a complete normal bake and freezing the final loaf. That's also a reasonable possibility, but if I'm to that stage and I know I'm going to freeze some bread, I often pull out some of the loaves a few minutes early, so I can defrost/finish baking them in the oven.

The one concern to that is that parbaked bread (in my experience) tends to stale a little faster after it is defrosted and baked, partly due to moisture loss during two stages of baking and two stages of cooling. If you don't plan on eating most of the bread right away after baking, I'd probably tend to either freeze fully baked bread (and defrost at room temperature), though the "frozen dough" method may be acceptable for richer bread doughs or doughs that don't depend on a high rise (e.g., pizza). The choice of method really depends on how much work you want to do at various stages, the type of dough/bread, and how quickly you plan to eat the finished bread.

I don't freeze large loaves often, but I freeze homemade bagels regularly, and baguettes or small batards occasionally. My personal preference is to freeze after the bread is baked and fully cooled; mostly to avoid dealing with any yeast issues related to freezing raw dough. Just wrap it in plastic wrap if you're only going to store it for a few days. For longer storage (up to a month) wrap it in plastic followed by foil.

Bagels thaw easily in the microwave for 30 sec and then toast to re-crisp. For crusty breads like baguettes and batards I warm them from frozen in a 400?F oven for 10-15 min. For softer breads or rolls it's probably best to thaw them at room temp and then warm them in a 350?F oven, 5-10 minutes, wrapped with foil.

I would freeze the dough before the second proof. And when you’re going to bake it, you can first defrost in the fridge and let it rise at room temperature before baking. This way you also ensure that your yeast is alive if it rises after being frozen.