Usually somewhere between 5 and 6 months would be the time when a male cat begins to reach sexual maturity and starts to spray. Although not all cats will do this, it is highly likely in unneutered males, especially if there are other cats in the house. That is why it is recommended to get them neutered before 6 months of age. Once a male cat begins to spray, neutering will help but it may continue to some extent if it has become a habit.