how do you know when to change locations?

I would say what kind of line are you running? if you are after some farther ranging fur bearers like otter(or even coyote) your sets may be there a week or two before they connect. If my 'rat sets dont get anything in 3 days i move them. Racoon, mink, beaver etc are more in the middle, maybe a week of inaction before I deside I am better off somewhere else. also depends on the sign you are seeing. when you see your fur on a whole line gradually drop off, and you figgure it is not weather, (or something else short term) it is time to move but exactly when is your decision. it is an inexact science trying to balence max. fur yield and the hassle of moving.

JoeRE is right. Main thing is to pay attention to the sign.

I agree with both answers. I let the sign dictate how many traps I set and how long they stay. I sometimes only stay a couple of nights and then move on. By gang setting, I can take the bulk of the coons and rats fast. Like posted above , otters, minkand coyotes may have a hunting cercuit that takes them 2 weeks to cover. Its a waiting game. Tony