We all have both. Don't waste either.

I would add, the sentence 'don't waste your time' is completely subjective. Some enjoy and find the energy in spending time apparently doing 'nothing' such as relaxing on a chair or taking a nap. To me, this is absolutely no waist of time, it is the activity they enjoy which pushes them to be way more mindful during the rest of the day, although some may consider it the opposite.