He notes that the interval between trimming will vary between animals. He notes that some cats and dogs are active enough to wear down their toenails. But in pets that don't accomplish this, overgrown toenails can cause problems. If your pet walks across a hard floor and you hear a clicking noise, its nails are probably too long. When the tip of the nail begins to curve downward, that dead tissue should be removed.
Many animals dislike having their nails trimmed.
But Dr. Paul mentions several techniques that may make the job easier. It may help to have two people for the job. Place your pet on its side and try to relax the animal. Cats are harder to restrain than dogs, so you might try wrapping the cat in a blanket and exposing only one foot at a time. Many cats also tend to relax if their face is covered with a blanket or towel.