Reasons why your cat suddenly urinates inappropriately:
1. When cats are in heat, they like to urinate everywhere to mark their territory, especially male cats in heat, who will do this to attract the attention of female cats. When they urinate, they will also raise their tails high and shake them rapidly.
2. If your cat has recently contracted a disease, such as bladder or urethral stones, it will feel frequent and urgent urination and will feel the urge to urinate at any time.
3. Urinary system disorders, intestinal and gastrointestinal discomfort, cystitis and other metabolic disorders can cause cats to lose control of their defecation, resulting in cats defecating everywhere.
4. When the litter box is not clean, the cat will not want to urinate in the litter box and will urinate randomly around the house. 
How to deal with your cat suddenly urinating inappropriately:
1. Appropriate spaying/neutering: If a cat urinates inappropriately due to being in heat, spaying/neutering can be chosen to prevent this behavior.
2. Take your cat for regular check-ups: Regularly check your cat's health condition, and seek veterinary treatment promptly if there are any urinary system problems.
3. Encourage your cat to drink enough water every day: Remind your cat to drink enough water every day to avoid urinary tract diseases caused by insufficient water intake.
4. Clean the litter box promptly: Clean and change the litter box regularly to provide a hygienic toilet environment for your cat.
