The best protocol to follow is to do assessments just before exercise, or, for the sake of consistency, always in the morning. Picking a consistent time of day helps make your scores more comparable to one another over time.

If possible, avoid caffeine-based drinks or other stimulants before the measurement, as these can affect your readings.

Try not to eat a heavy meal before the assessment, since digestion can also influence your results.

If you're doing the assessment in the morning, give yourself some time to fully wake up first rather than measuring immediately upon waking.

Despite these recommendations, the most important thing is to do the assessment whenever it fits into your daily schedule best — consistency and ease of use matter more than hitting an exact "ideal" window. If your timing varies, simply keep in mind what variables (caffeine, food, exercise, sleep) may be affecting your measurement at that particular time, so you can interpret the score with that context in mind.