Claws are a cat's weapon. When a cat is attacked or has the intention to attack, it will show its bright claws as a show of force, to intimidate people and other animals. Nowadays, domestic cats have been trained and cared for, and their claws are not as sharp as they used to be. However, you may still have the chance to witness the power of a cat's claws on some furniture or on your owners. 
Should cats have their toes trimmed?
In the past decade, data from the United States and Canada shows that many cat owners have had their cats' nails removed by professional veterinarians. The main reason behind the popularity of nail removal is the increasing number of pet cats in cities being kept indoors by owners with a "luxury furniture" mentality. Therefore, the cats must undergo this basic nail removal service to live in their owners' carefully furnished homes. This process is done to prevent the cats from scratching their "expensive" furniture. However, nail removal has only been around for about 30 years. Clawed cats have been living indoors for much longer than that.
Decanting removes the bones, tendons, ligaments, and the first phalanx of each paw from a cat. Decanting deprives a cat of a vital part of its life and is one of the most important parts of feline anatomy. Simply put, a decanted cat is a disabled cat.
Leaving aside the physical pain caused by declawing, the psychological impact on cats is also enormous, causing them to completely lose their ability to climb, chase, hunt, and socialize.
According to a 1994 veterinary clinical scientific report from Washington State University, of 163 cats that underwent declawing, 50% experienced one or more complications immediately after surgery, such as pain, bleeding, disability, and weight loss. Further follow-up of 121 cats showed that 20% developed persistent complications, such as infection, rapid weight gain, prominent bones in the claws, and intermittent lameness (abnormal gait).
Just to prevent cats from scratching furniture or injuring people, some people cut off all of a cat's claws... It saves people some trouble, but the cat is rendered useless. You see, cats use their claws for friendly or unfriendly social interactions with other cats, for running and climbing, and for hunting and self-defense. You could say that without claws, a cat, besides still meowing, has lost all its feline characteristics.
A cat's claws serve the following main functions:
1. Cleaning:
A smooth, clean coat is essential for a cat's health and happiness. Temperature control, cleanliness, waterproofing, and maintaining their scent signals are vital for a cat's survival. Studies show that cats spend a significant amount of time grooming themselves each day. This includes not only the typical licking but also repeated scratching. This scratching is a key part of their daily grooming routine: relieving itching, removing loose fur, and combing away tangles. Without claws, neither humans nor cats can effectively scratch themselves. The entire grooming process would be extremely painful. Even daily brushing by their owners cannot replace the pleasure that natural scratching brings. Anyone who has an itch they can't scratch (or can't reach the itchy area) can understand the awkwardness of having a declawed cat.
2. Climbing:
Climbing is the second most important instinct for felines. In fact, no amount of punishment can extinguish their desire to climb. If a feline attempts to climb after its toes have been removed, it will be the greatest punishment of its life, as it will no longer be able to grasp anything with its claws and nails. If it ventures outdoors, it will be even more dangerous. If chased by other cats, dogs, or hostile humans, it will swiftly flee to higher ground at the first opportunity to escape its predator. As it leaps onto walls, fences, or trees, it uses its no longer-existing claws to grip the surface. It will find itself sliding downwards, eventually crashing down in front of its predator.
3. Defense:
When facing an enemy, when it needs to protect itself, it will be in a very disadvantageous position. When it swings its claws, it has already lost its defensive weapon. Often, the pain caused by those small, sharp claws alone can make it teeter on the edge of life and death.
4. Hunting:
Not only does de-clawing impair a cat's ability to clean, climb, and defend itself, it also destroys its hunting ability. "Ah," you might say, "it doesn't matter to my cat; it's a carefully raised family pet." But this carefully raised cat might one day get lost on the street or become homeless, quickly dying of hunger. The essential grasping motion for a predator with sharp claws will become a useless posture. 
How to trim and care for cat claws:
Between nail trimming and excessive scratching, most owners opt for regular nail trimming. If you start this process when your cat is very young, it's a very simple task, although most cats eventually accept the procedure.
Specialized tools can be purchased at pet stores. Look for suitable tools (do not use human nail clippers, as you might accidentally crush or injure your cat's paws). Also, the sharper the blade, the easier the process will be. A blade with a short, hooked edge is ideal; this may be easier for someone to handle.
Secure the cat in the crook of your arm, on your lap, or perhaps with both legs to pin it to the floor, depending on the size of your cat and yourself. Hold the cat firmly on the ground in the crook of your arm, immobilizing it, and grab its paws with your hands (sometimes it will escape from under your arm; it takes practice). Position the cat so its back is facing you, making it impossible for it to scratch you or easily escape. Hold nail clippers in your skilled hand. Squeeze the cat's paws with your hands; the nails will break open.
Carefully examine them (you must do this step before actually trimming; try to familiarize yourself with the structure of its paws). If the paws are white (most cats are), the nails and the flesh are easily distinguishable (in good lighting, of course). You can see that the tender flesh under the nail is pink at the base of the nail. The skin attached to the nail and the part that grows out behind it are very easy to identify. Never cut into the tender flesh underneath.
Your cat will be in great pain, and there will be blood everywhere. When in doubt, try to trim less. Of course, this means you'll need to trim more often.
Trim each toenail on the tender skin, and don't forget the "thumb." For cats, the "thumb" is only on the front paws, equivalent to the human thumb, and it never touches the ground. Some cats are polydactylous, with up to seven toes on one paw. Usually, each paw has four nails, and each front paw also has a "thumb."
The hind paws don't need frequent trimming or any trimming at all; they grow slowly and aren't very sharp. You must hold down one of the four paws; with practice, it will become easier. If you still can't control your cat, it's best to ask someone for help. Then you can pick up its paw and do the job.
Declawing is a selfish choice made by irresponsible owners, and some European countries have declared it illegal animal cruelty. Therefore, for true cat lovers, scratching posts, love, and patience are key. From kittenhood, whenever your cat scratches furniture, simply place it in front of the scratching post and repeat this patiently several times. The cat will then understand your intention and usually stop scratching. Furthermore, understanding your cat's temperament and regularly trimming its nails will also ensure a pleasant relationship. Alternatively, if your cat is particularly mischievous, try using plastic nail caps. Replacing them every few months allows your cat to retain its own nails without damaging anything in your home.
