Is one thyroid level right for everyone? or does that depend on the specific person?

Normal Levels: The same normal levels are for all individuals, however this may vary slightly depending on the lab. Usually normal levels are based on averages and have both a higher and lower levels. Different labs have different reagents and use different methods, so there upper limits may be slightly different.

Some mild variation: Thyroid hormone test results are similar for all persons, with some variation in the "normal ranges" depending on age and sex (which is true for many types of blood tests). Sometimes, a person will have results inside the "normal range" but still need treatment; while other times, a person will have results a little bit outside the "normal range" but still be normal (nature is just this way!).