Q.How far will mint runners go
I have planted some spearmint, chocolate mint, and lemon balm. Everyone says they will send out ”runners”. But no one has told me how long these ”runners” will get. You can tell me from personal experience.

Certified GKH Gardening Expert
The spread out from the original planting and how far they go depends on things like how loamy your soil is, how much water and nutrients they get and what type of weather you have.
Given the right environment, they can spread several feet in a season. Other environments, they may only spread a few inches.
Regardless, when planting a mint plant, I would strongly recommend putting barriers in place. Even if it spreads slowly in your garden, it will spread.