Deer ticks are bad. All ticks are a problem. I have been giving my dog a new heart worm preventative that also helps with ticks. It is called Simparica Trio. I do not know if they make a version for cats or not, but my dog seems to like it more than Trifexis which he would not eat on his own. I had to hide the Trifexis in his food, and even then, it often made him regurgitate. I have had three dogs not want anything to with Trifexis. That says a lot to me.....
Still, I think if you are not near woods and do not go camping, etc., your animals are probably safe from deer ticks. They might spread Lime Disease....not sure.