I generally do not take any intervals during my walks. Some of friends say that taking intervals is necessary for regaining stamina which allows us to walk a long distance.
I take a break before returning back during my walk and this gives me the rest I need. Taking frequent breaks does not do good with regard to losing weight.
Initially, I used to take a lot of breaks while walking but now I have reached a point where I do not require breaks. I just keep walking till I get back home.