Change your routines often. Like the day you took the cat to the vet.
And make note of his patterns...does he appear at certain times of each month - like when there's a full moon? Certain time of the day? Human beings have patterns, we just need to pay attention to see them.
My RAH used to say I would make a perfect target for a serial killer because I was so routine oriented. Don't be me. Be unpredictable.