There are several considerations about whether a Cavalier King Charles Spaniel will be a good fit for you.
One important consideration is their moderate energy level. Our three Cavaliers love playing in the back yard, but they won’t necessarily quit when they should, so we have to make sure they don’t overdo it. Cavaliers want to please you but they don’t always know their own limits. If you are looking for a high energy dog that can run flat out all day, then Cavaliers are not the dog for you. They can do very well in agility and other dog sports but their energy and endurance is much more limited than, for example, a Border Collie.
Cavaliers have been bred for generations to be close to their people. They cuddle, they may lick, and they follow you around. You are the center of their lives. They want to cuddle on your lap. They want to sleep on your bed, if you’ll let them, preferably snuggled up next to you. They would be unhappy kept away from you or in an outdoor pen. If you want a loving, gentle, loyal little dog, Cavalier King Charles Spaniels are a wonderful choice.
Cavaliers are little dogs. Most are 12 to 13 inches tall and under 20 pounds. They are not extremely fragile, but they are small and not suitable for the rough play young children can engage in. If the child is six or older and able to be gentle and follow your guidance, then a Cavalier will make a wonderful companion.
I can’t speak for all Cavaliers, but ours, and any Cavaliers we know, get along with cats. Our cat Moxie mostly ignores the dogs, although she does initiate play with them sometimes. The dogs are very interested in her, but respect her boundaries. Moxie is not in the least afraid of them.
Cavaliers are not tough dogs that can take rough handling or extreme environmental conditions. They need comfort and care, and the love you give them will be returned many times over to you by your Cavalier.