An optimal range is 700-900 ng/dl and more importantly a free range of 100 ng/dl to 150 ng/dl. Free measures how much T you use and how much is not bound up to SBGH.
It is also important to measure DHT levels. You may have optimal levels of T if you can block the conversion of T to DHT. Saw Palmetto works well for blocking DHT.
Bottom line is this, if you have morning wood every day, you probably have optimal levels. three times per week is okay, once a week is bad, once every two weeks and you are barely a man
Other tests that are worth doing are:
Candida is also a great thing to have checked. Unfortunately it requires a stool test which is never pleasant. If you have sugar cravings all of the time you probably have candida.