A cat collar can be a lifesaver because it is a clear visual signal that a cat is owned and therefore domesticated. Domestic cats are protected because they are owned by somebody. To take away or trap a domestic cat and perhaps harm them might expose the person to a claim for damages. In general people are aware of this.
So cat collars can be useful in that sense. They are, however, a duplication of a better form of identification namely the microchip. If a cat is micro-chipped then they can be identified. If they end up at the shelter they are therefore protected and there would be a much smaller chance of them being euthanised.
The problem with cat collars is that they are potentially dangerous. It is worth mentioning, too, that microchips are not 100% safe either. There’s a third way of identifying a cat: a tattoo on the inside of the ear flap. This may be safer than either a collar or a microchip but it is very rare.
I’ve got to answer the question in the title but there’s no clear, black-and-white answer to it. It is a personal decision. A cat owner should be guided by the way their cat responds to wearing a collar. Some cats are more resistant to it than others.
This brings me to the first point which is that you can’t put a collar on a cat and then walk away presuming that everything will be all right. You have to supervise your cat and make sure that they accept it or become used to it. It is suggested that you should watch your cat for an hour or two after putting on a collar for the first time.
It is also suggested that you should put a collar on, watch your cat for an hour and then take it off. You can then put it on again once you feel your cat is acclimatised to wearing it. It would be unwise to force a collar on a cat if they find it too uncomfortable and unnatural to wear. This is because it may be unsafe to insist. Most cats adjust to wearing a collar.
A study by Ohio State University found that 9/10 cat owners plan to keep a collar on their cat after the study had been completed. This points to the possibility that the majority of cat owners would like their cat to wear a collar but are concerned about the safety issues and the potential problems of getting their cat used to it.
These days, collars have safety features. The collar must be safe. You might like to discuss the matter with a veterinarian if they sell collars. The buckle should be a breakaway type or the collar should be elasticated. You should be able to slide two fingers under the collar when in place.
These features are to avoid a cat becoming entangled in their collar and perhaps strangled or getting their foreleg caught in the collar as they try to remove it (see picture). Also the ID tag should not be a potential threat to safety. It should not be the sort that might be snagged up in something causing the cat to panic and harm themselves.
There is another potential hazard: plastic collars can melt in hot sun. This would harm your cat. Buy non-plastic collars. Buy a quality product.
The bottom line is that domestic cats can look nice in collars and they can be a good safety feature but they are unnatural and therefore a cat might need time to get used to it and they may reject it.
Should I put a collar on my cat? Yes, if your cat accepts it and you are sure that wearing it will be safe for your cat.
P.S. The conclusion is a personal view. Yours might differ. Is so, please tell me.