Bottle Conditioning - When to move into refrigeration

Following the advice I've read on these forums, I'm letting my beer bottle condition for 3 weeks @ 70f.

At what point should I move the beer into refrigeration to further age? Thanks.

When they are carbonated. Moving them prior to that will just prevent the yeast from making CO2. The three weeks is a minimum and not an absolute.

Agreed, once they are fully carbed you can move them to refrigeration. You could also leave some in a cool dark climate like a closet to age and compare them against the ones you age in the fridge.

I usually bottle at least 1 from each batch in a plastic soda bottle. When it's rock hard, they're carbonated reasonably well but since that usually happens within a week or so for my batches, I tend to wait an additional week past that before opening one. Taste may be better if you go even longer at cellar temp vs fridge temp, so try the "experiment" BryceL suggested above.

I fridge mine as I need them. So I always like to taste the carb after a week. so I throw a bottle or 2 in the fridge, then a few days later throw a few more in. And do that until I have as many beers as I need.

As far as cellaring goes, you can do that but it's not recommended to do it to anything below 6% abv and unless they're uber beers (like 90 Minute) not recommended for overly hoppy beers either. Though if you want to see what cellaring does to your beer, knock yourself out.