Do you need to measure ketones? No, probably not.

Is it helpful to have data? Yes, it helps to debug, and especially when your just getting started, or when your pushing your carbohydrates up to see what your limit is.

While Lauren does a great job reviewing all the options, I think the keto mojo is the easiest, cheapest, and most accurate method. https://keto-mojo.com/

If you do decide to track your ketones, try to do it at the same time every day, a few hours after you have woken up, but before you have eaten.