Another Wine and Diner just back here. I was planning on that being a long run weekend, but obviously that was a bust.

So I felt I had to redeem myself, and get going with training for this full, so yesterday I did my longest run to date, 16 miles! I'm sort of blown away that I actually did that, but also blown away that I have to do another 10 on top of that.
For those of you who have trained for a full before, what was your longest run before the actual marathon?
The key is that you don't want to exceed more than 3 hours of running (during training) - in general. I realize for some slower paces you might have to. I've just read that going past the 3 hour mark can result in your body being more susceptible to injury so it is not recommended - and you don't necessarily gain anything physiologically going that long (other than time on your feet). Again, this is probably a little different if you have a slower pace, so others can chime in with more expert advice. good luck.
I'm usually 4 hours for the 20 miler--and I need it. Honestly, especially for slower paced people like myself, it's good to have that time when you want to quit and pack it in but you learn to fight it on the long run. So aside from just "time on my feet" it's time fighting with my brain if that makes sense. Knowing "I don't want to but I still can" is a nice boost come race day.
Essentially,
@CamColt this is what it comes down to. The debate as to whether it is better to teach the body/mind to be able to run for 4-7 hours, or whether training for a longest period of 3 hours is physiologically sufficient. My advice comes from the physiologic standpoint, as little seems to be gained physically from doing exercise longer than 3 hours and the risk of injury rises dramatically. However, I do understand the counter (mental boost and time on your feet).
I personally feel this mental edge could be accomplished by doing more Saturday/Sunday runs if you have the time for it. If you decide to max at 3 hours on Sunday, then you could do a max training run of 1.5 hours on Saturday to reduce the freshness you are coming into Sunday's run with. This means you'll hit the same level of tiredness as the fresh Sunday, just sooner, thereby reducing the amount of time necessary out on the road the 2nd day. However, there is a HUGE caveat with this information. A training plan should be viewed like a symphony. Rather than solely focusing on the brass or woodwinds, we need to remember how all the instruments come together to create the beautiful music we desire. Be careful using what I say and focus on the 1.5 hour Saturday run and 3 hour Sunday run, but forgetting the importance of the rest of the week.
For me, I've maxed at the following...
1st Marathon - 20 miles x1 (3:34) (max per week 26 miles) - Time 4:50
2nd Marathon - 20 miles x2 (3:03, 3:07) (max per week 48 miles, Dopey training) - Time 4:35
3rd Marathon - 20 miles x4 (2:50-3:24) (max per week 31 miles) - Time 4:20
4th Marathon - 17 miles x1 (2:46) (max per week 42 miles, Dopey training) - Time 4:27
5th Marathon - 20 miles x2 (3:14) (max per week 43 miles) - Time 4:58
6th Marathon - 16 miles x3 (2:28) (max per week 60 miles) - Time 3:38
My 6th marathon was BY FAR the best experience I have ever had running a race. Never felt overly tired and finished very easily.