This is a pretty big topic so it's going to be difficult to do it justice in short space. As you know, cocoa butter is polymorphic, and when you've got 'good temper' (lets define good temper as CTU<10 and slopes between -1 to +1) - a good 60% of the cocoa butter in your 'solid' chocolate is still actually liquid. That liquid cocoa butter will slow crystallize (which is one reason your tempered chocolate gets harder over time), and your 'good temper' crystals will convert to a lower energy state crystal (which is harder - another reason your chocolate gets harder over time). The mechanics of flavor release are heavily dependent upon how things melt - so aged chocolate will taste different than freshly moulded chocolate because it's releasing flavor differently due to how it's crystals are melting. Essentially - for 'good tempered' chocolate (as defined above), after 30 days of being stored in an iso-thermal 70F(ish) environment - your flavor changes slow to the point where it's less meaningful (they still occur, but the average bear can't detect them). Melting your chocolate bar and recasting it resets this. Most people are really surprised by how different their 'fresh' chocolate tastes compared to their 30 day aged chocolate.

But wait, there's more. There are a few more mechanisms of flavor change. One of them is evaporation - your volatile flavor compounds, well, evaporate. It's why you can smell chocolate - chocolate 'flavors' are in the air - and over time, enough of them will evaporate that there's less of them in your solid bar, and it now tastes different. Melting your tempered chocolate will not reset this - once they're gone, they're gone.

And then there's oxidation. The fats in your chocolate undergo a chemical reaction called oxidation (and possibly one called hydrolysis if there's moisture present). This affects milk and white chocolate more so than dark, and will happen regardless of if your chocolate is tempered or not. Remelting your tempered chocolate has no impact on this.

So, as with many things - i'm afraid there's not a straight forward answer.

@bethingbird @Sebastian - my understanding based on a long conversation with Ed Seguine is that if you were to take the same chocolate and store it tempered and untempered for the same length of time (at least several months) when you tasted them they would taste different. One explanation here is that the difference in crystal structure will affect melt and the release of aroma and flavor chemicals.

However, Ed says that if you de-temper the tempered chocolate and melt the untempered chocolate and then temper and mold each, the results will taste basically the same assuming the two chocolates were stored under the same conditions. Does that accord with your understanding, Sebastian?

As the use for couverture is to temper and then use for molding and enrobing, then I don't see that tempering before storage results in a meaningful difference - if this is the case.

Some makers I know use what are called fish containers to block and store their chocolates. Contact Consolidated Plastics and ask for John Conley (please mention my name). Get the short square containers (~10lb). You can pour the chocolate into the containers and the seal is tight (burp like Tupperware). They nest/stack easily and are easy to label with painter's tape. These boxes have lots of uses around the kitchen.

whoops - do you have to temper it? No. Do you have to store it < 2 years? No. is it better to do those things? Yes.

Wow - whole lotta questions there 8-) generally speaking - minimize exposure to air, light, and humidity. Products with dairy in them will not last as long as products w/o dairy. 2 years is a long time to store chocolate. Storing chocolate tempered is always going to be better than storing it non-tempered (long explanation involving polymorphism and flavor changes over time), plus it's easier to work with for smaller customers.