How long is it supposed to last?

This is my second beer, and so far, on both brews, the fermentation only lasted two and a half days.

This most recent beer was going crazy within 12 hours of brewing it, and was bubbling so hard I contemplated switching from the airlock to a blowoff... and yet... I brewed it sunday morning, and here it is Wed. and it isn't bubbling a bit. This morning it was bubbling about a bubble every ten seconds or so...

The temperature has been consistent and is right in the middle of the range that the yeast is supposed to be at...

Am I wrong in thinking that it should ferment longer than this?

OG was 1.048, and I don't want to pop the top just yet to check it again...

I've had fermentations go from 24 hours to 2 weeks and they've all been normal. Often, the warmer temperatures cause yeast to work faster, so some of the faster fermentations I've had have been in the high 60s. My slowest tend to be lagers, or ales fermented cool. It really doesn't matter if it goes fast or slow, as long as you're in the yeast strain's optimum temperature range and pitched enough yeast at the beginning.

Usually, though, it's about 3 days of active fermentation in most of my ales.

Ok, thanks. That's reassuring. I thought I f'd it all up.

Innitially, I pitched two packs of rehydrated dry yeast... I figured the more the merrier.

How are you measuring the temp? If your measuring ambient temp where the fermenter is, the beer itself can be quite a bit warmer than that.

The sticker thermometer that came on the fermenting bucket.