Academic question on fermentation

I still have my first brew in the fermenter but I'm wondering about ferment times:

1. If you are getting a good FG reading (ie about 25% of your OG) and no more bubbles in your airlock, then is there any benefit to continue to keep your beer in the primary?

2. If you are getting a good FG reading and no more bubbles in the airlock, is there a general time limit before you bottle? I'm wondering if after "X amount" of time in the primary the beer either stales, or you need to add more yeast for carbonating in the bottle?

BTW, after 2 weeks in the primary my American Pale Ale II is still giving me a bubble every 2.5 minutes. I'm going out of town the week of Thanksgiving and was hoping to bottle before I go so that the beer would be ready for a holiday party December 12. Patience is a virtue of which I have very little! Although, I have not pulled the cork or opened the fermenter in any way since I pitched the yeast. I'm trying really hard not to mess with it at all, but I'm like a kid trying to sleep on Christmas Eve since this is my first ever home brew!

If your FG is where you want to be and stays constant for 2-3 days then the ferment is done. Leaving your beer on the yeast/ in primary for 3-4 weeks helps clean up the process. You might bottle just before you leave and be good. Keep in mind that airlock activity does not always signal the correct info that only the Hydrometer can give you.

We once had one that slowly bubbled for over a month when the hydro didn't change after week two.

2. It's a good idea to bottle within 6 months, but one member bottled after 13 without a problem.

First off, forget about the whole bubbles in the airlock thing. It's meaningless.

Yes, there is a benefit to leaving your beer on the yeast after fermentation is done. The yeast will tend to "clean up after themselves", taking up various compounds we don't want in the beer.

A "time limit" for bottling would depend completely on the beer. A small beer like a Mild would be ready to be bottled in a couple of weeks, and start going down hill after a few months. A beer like an Imperial Stout on the other hand, would actually benefit from sitting around for a long time. I would want to get it off the trub after a couple of months, but that's it.