My cat hasn't changed it's behaviour at all but is squinting his left eye. He has done this before and it was just some sort of thing that like 15% of cats get. They gave him eye drops and he was fine. Now he is squinting again and his left eye is watering quite a bit. Should I take him to the vet? We have some eye drops from last time. Should I use those?

For those of you who wanted to know, he has now healed up. It was just a simple infection. Thats why I was hesitant to bother the vet, because we had some eye drops from when he had that last time. Thanks for the help.