After several half marathons and trailruns of around the 25km, I started training for my first marathon on the 15th of Octobre this year. Currently I'm running about 4 times a week with the longest run about 24km (15 miles) without getting into trouble. Running a total of 55km (34 miles) a week. Steadily (without exaggerating) i'm building up my training volume.
A friend of mine (who already ran several marathons so far) advised me to incoperate some speedwork into my training. However i don't want to race within a specific time, I just want to finish without suffering too much.
So my question is, what are the benefits of speedwork during marathon-training? Keeping in my mind that I won't race to arrive within a specific time. Wouldn't it be better just to keep increasing my milage at a steady pace?
Note: I did ready up on some internet-pages. But they all seem to refer to a better finishing time.