Is temperature tolerance really that expensive?

[vitruvian]

Originally Posted by Anthony

A steam hex is treated as doing the same damage as a fire hex, despite the fact that a hex of steam is likely under 300°F and the hex of fire is likely above 1000°F. Lava has about the same temperature as a bonfire, but does far more damage. A tight beam burning attack doing the same raw damage as a fire hex is probably above 3000°F.

Nothing in the text of DR implies that it's categorically different from other types of armor, and it certainly can represent X inches of mild steel or whatever -- a typical robot, for example.

DR bought in a character writeup is not ablative unless you take Ablative or Semi-Ablative. Period.

Therefore, DR without such limitations will protect against damage of the types it's good against each and every turn, forever. There is no difference with longer term exposure.