Well, you always want to be well hydrated. If you're drinking plenty of water through the day, you're good.
Those machines are really just snake oil. They cannot accurately measure the insides of your body with electric impulses. I believe the "hydration levels" are the least accurate fancy feature of them - followed closely by body fat/lean mass measurements. I've seen people post that they can be measured, get off the scale and get back on again, and get a completely different number.
You will do much better to just track your water intake on your own. As my choir director used to tell us, if you're peeing clear, you're drinking enough