depends on how many terriers you have i suppose .Some people dont have the time to walk all their terriers 2 maybe 3 times a day.Personally i walk two terriers at a time and one lurcher ,then i have to walk another terrier ,teagle and a lurcher later that evening if i can.The only thing i am thinking though is that during the summer months with a a few terriers on a thread mill and not working ,would they be too wound up