I don't own an iPhone X but if I had the money I wouldn't upgrade to the new iPhone Xs. The reason is because iPhones are notorious for adding very little to the 's' variants of their phones as opposed to the normal versions. I guarantee that the difference between the two phones will be miniscule and almost unnoticeable. I'm not trying to shame Apple but I honestly believe that they churn out the same phones twice a year and give them exuberant prices.

As for how often I change phones, I try to make sure that I change my phone's once a year, that way I'm using devices that aren't too old and are up to date with the current trends.