My first cat was an only cat for 10 years before I brought in #2 (I now have 7). Cats #4 &#5 were siblings kittens when we brought them in, as were #6 & #7. I can tell you from experience it was much better having two kittens together than one lonely one. They will do so much better having someone to play with. If I adopt any more kittens I will always try to get a pair for their sake and mine.