When does a space limit issue come into to play?

I mean, heck I know final fantasy XIII came on like 3-4 disks? An the overall length and scope of the game don't even compare between each other.

How is Skyrim able to add such a LARGE gaming enviorment, with various towns, cities, npc's, animals, gaming elements, etc...An still manage to fit even more and more content with these various updates and DLC's?

Are other developers just lazy and don't use the full opportunity to max out the space limit..or does the xbox have more space than I was lead to believe?

Because you have to imagine adding anymore content will simply quote, unquote, "buckle the bridge"

reusing same voice/dialogue

Microsoft updated their disc format prior to the release of Halo: Reach, which reportedly gave developers another gigabyte of room to play with (but still less than a blu-ray).

However, the big factor is cutscenes. There are very few in Skyrim compared to most games.

Edit: Voice dialogue to a lesser extent.

Because the Dovahkiin made it so

I have often wondered that myself. I mean, they reuse a lot of textures and voices, and duplicate a lot of the items and props in locations etc, but ... it's undoubtedly a mahoosive game to cram onto one disk. I mean LA Noire came on 3 disks. That always seemed odd to me.

Because it's [censored] Bethesda.

^ this

Because they don't use that much space in the first place.

Beth use the same asset (mesh, texture, audio) over and over again, mostly they play variation with textures and audio. The textures are mostly 512x512, so score another one for space saving. They also don't use cutscenes in the form of video, although it's hardly new, it does save space (that Bethesda logo video you see at startup consumes more than 20MB, just for a few seconds).

IIRC Skyrim's biggest assets (ones that consume much space) are meshes and audio, with textures number 3.