My first full playthrough was 40 hours on the dot (human mage), with Leliana, Alistair, and Sten as my regulars. Over 75+% of all side quests completed.

Second playthrough was 35 hours, (human warrior). Alistair, Leliana, and Morrigan as my regulars. Again, 75+% of all side quests, but I'm pretty sure I got a few more this time.

Third playthrough, 26 hours and counting (city elf rogue), I'm about 3/4 through the game at my estimate. Companions are a great deal more mixed this time. I swap Morrigan and Wynne whenever I feel like it, and Alistair occasionally gets swapped for the other rogue [not naming him for spoilers' sake].

I never use Shale, he always hits the rest of the party with AoEs and usually dies anyway, despite his massive Con.

I've got a few other characters, but I'm not really playing them seriously.

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I absolutely had to start over. My first mage build was horrible.