Basically since last year's NYCM I have been very lazy. Not in terms of mileage (I do about 45-50mpw) but in the runs themselves: very little fast stuff, most miles done at a lackadasical easy (8:00) pace). My best marathon is 3:10 and I would love to break 3 one day. Best half is 1:24 and change.
So here's the question. I'm planning on doing a November marathon and will probably follow a Pfitz plan. In the meantime should I continue these slow lazy runs or should I start incorporating some tempo and speed work?