Don't worry yourself too much, it's common for a cat to block and never block again throughout a long life as happened to two of my male cats. I found out from research after Teddy blocked years ago that eating his favorite treats - raw oats soaked in water and cashew nuts that he stole from a bag if I accidentally left it on the sofa, actually made blockages more common. From then on there were no more oats and the nut treats were very, very rare. I didn't even have to switch him to mostly wet food, which he didn't want anyway, just to a better dry food - Royal Canin.

I know how frightening it is, though. When the first cat blocked, My Artful Dodger, I spent years checking on him and making a few panic rushes to the vet.