i hated the idea of harnesses, UNTIL i had a toddler who was running off in public, esp car parks. Then i changed my mind VERY quickly.

we had a monkey harness that lived in mummy's car and a koala harness that lived in daddy's car, so no matter where we went, there would be a harness. My child liked them so much, she was excited to put on her "pak pak" as she called them. It was like putting on a plush toy on her back.

i had the harness on her, would gather up the long bit, put the loop thru my wrist, and we would walk hand in hand. So she was not being "pulled" on the leash, cos we walked together. And then on the times she really did want to run off, i had notice it was happening. i have RSI, so her running, pulling on the full length - no way i could physically cope with that.

So i mitigated the leash (to myself), by making sure i didn't yank it, or have it out "long", most of the time. if it awas out long, that meant i needed to drop whatever i was doing, and manage her behaviour. i have no idea how to manage with more than one child, i have one child, so my only experience is using the leash with one child.

developmentally, we used the leash until she could understand and go along with the "we don't run off" stuff. we stopped using the leash when she no longer needed it. it was only a short time in the scheme of things (say, a year) but if made going out in public so much safer.

i don't like seat belts either, but they save lives, so we wear them. For the greater good etc etc.