You might always want to walk around with your ferret. It is not like a dog that you can let out and then it follows you. Moreover, ferrets are tiny and they might even disappear which needs you to have a harness. With a harness, you will have a way to have a large part of the chest covered and then have the harness tied on a leash that you can always hold as you walk around with your pet. The best ferret harness is said to be the H-style harness.
For the safety of your ferret, it is very advisable to avoid the use of only a collar on your pet ferret. Make sure that you obtain a harness. Collars are not good because if you tighten it up so that the ferret does not disappear then it will be too tight to choke it. It can also make the fur to wear off and leave an exposed skin that may be prone to infections. In such a case, this would be posing health problems to your ferret. A harness is very safe for use in such cases. However, you should always avoid leaving the ferret with a collar or a harness while in the cage. This is because it might get caught in somewhere in the cage hence choking the animal to death. This means that a ferret that has a harness or a collar should always be supervised. It might also be a little weird to use a harness when inside the house. A harness is put to better use when walking the pet outside.