Call me a purist, but for me and all of my competitive running friends, marathon training is ALL ABOUT THE MILEAGE!
As I've discovered over the last several years, you can't fool your body into running a fast marathon without doing the homework. Putting lots and lots of miles "in the bank" is the way to go.
Forget about speedwork. If you are stretched for time, get more miles in.
I started running in May 1993. I gradually built up my mileage and for the year 1996 through 1999 average 3,500 miles per year (yes, that is an average of 9.5 miles each and every day).
That was a LOT of work, but those were my best marathon years, when I ran a 2:37 in 1996, 2:35 Personal Best in 1997, 2:37 in 1998 and 2:36 in 1999.
Things kind of went downhill after my 2:35 because I didn't let my body recuperate long enough and injured myself doing speedwork and too many races. That led to groin pulls, hamstring ailments and other problems.
That was a long time ago and I'm a lot older now, not to mention tired, working a full-time job with a family and kids while I blab away about my training and other topics here on Conejo Valley Guide. But I'm just happy to be training, fit and healthy.
Last year's mileage for me was 2,092, slightly higher than my 2008/2009 total mileage. I've averaged roughly 2,000 miles per year over the last 3 years. That's quite a bit less than my peak mid-1990s mileage, but enough to enable me to run moderate marathon times in the low 3 hour range at my advanced age of 46.
I've been tracking my mileage on an Excel spreadsheet that has grown to over 6,500 rows since May 1993. It shows I've run 44,993 miles through December 2010. Maybe I do need to get an oil change or have my filter replaced at least!
I also track the number of minute run each day. As of 12/31/10, I had run 15,744 minutes in 2010, which equates to 262 hours. Damn, that's a lot of time! But worth it.