Good all round advice, managing the slack is important. Even a small/medium sized dog can snap a clasp if they have had enough room to build up momentum or if the clasp doesn't break they could be injured by the sudden jolt to a stop. Never.. ever use those retractable leads for 4 main issues, firstly they tend to break and the end of the lead could come out of the housing losing control of your dog, the line to save space is usually very thin and peoples natural instinct is to grab the line which has caused severe injuries due to rope burns or in same cases near complete amputation of fingers. Thirdly because the line is so thin once your dog is at full extension you have no way of pulling them back to you if they chose not to return or if they are prevented from doing so like being grabbed by another dog and finally I have seen some videos where the braking mechanism of these devices was not robust or not activated allowing a dog to take off, build momentum and once reaching the end causing their owner to be slammed into the ground as they were pulled by the sudden force. Lastly if the area you walk your dog is prone to moisture, dew, or grass clippings go for biothane, I found the fabric webbing leads just soak up water and get clogged with grass and dirt very quickly.

Lines top jaw is snapped of now is this why behind the dog was a lizard with a blue eye became a crab pincer? 😭

Seems a lot easier with a retractable lead

wear gloves!