Build up to your marathon

Do you do your long run every 2 weeks or every 3? While I’ve always adhered to the 2 week philosophy, I’ve read many programs that recommend doing your long run every 3 weeks. Thoughts?

I’m not sure I understand your question, but I do a long run every week. For 2 weeks, I build distance; the 3rd week is a recovery week and I back off a little on the mileage. I know other folks build on the big miles for 3 weeks and then back off for 1 week.

I usually do a long run every sunday with shorter runs throughout the week. I’m training towards a 50k in feb so I add ~1-2km every week for two weeks, then on the third week don’t add anything (moving from a half-marathon base)