In all games I try to create always the same character. Even when I replay the game I choose the same character, it is not a matter of time or energy, it is a choice.
Of course it also means I always plays the same style and miss some options, don't accept some quests and so on to keep the character consistent.
This is just how I like to play the game.

i usually play one toon all the way through the mainquest on vanilla. For TES games i like to match the race with the game, Morrowind: Dumar, Oblivion: Imerial, and now Skyrim: Nord. After i will load up on mods and such with subsequent playthroughs.

Exactly how I play right there. No matter what other characters I may create to try other combat styles or professions etc, I have a special place in me heart for my (in this case) second character.

I have 3 characters presently.
Different builds/races for different roles/questlines.
No one character should be able to do it all, so through different builds I get to see the whole game without creating that hated do-all tank.