I have a serious problem with the tea section. It is simple, but not that simple. The minutes may apply to western-style of brewing, but definitely not Chinese (Gong Fu) style brewing. In there you use much more leaves of tea and brew for a much smaller period of time (30 seconds might already be too much.) Continuing on this note, the steeping times should be correlated with not only the type and quantity of tea, but also the water temperature. It is generally advised that for instance green teas be brewed at lower temperatures (75 - 85) degrees Celcius. If you are brewing at 85, steep it for less, if you are brewing at 75 take a bit more time. One thing to note that if your green tea is scented e.g. Jasmin scented green teas, one should steep at a higher temperature than usual green teas. Another thing - Japanese Sencha green teas should be steeped for far less time than more traditional Chinese green teas. (Longjing for instance)There are also other varieties of tea - oolong and white teas among the more common. All teas differ in the level of oxidation. Black teas are most oxidized white teas are least oxidized. Oolongs differ - they more oxidized than green teas less oxidized than black teas. Their brewing time / temperature also depends on which end of the spectrum the particular oolong you buy is at.
On the less common end of the tea spectrum are the Pu-Erh teas. These are aged teas. You should treat them as black teas in terms of brewing. Except rinsing most of the Pu-Erhs, especially Pu-Erh cakes is advised. A more obscure tea (though it's getting more and more popular) is the matcha green tea. The brewing process of matcha is very different. If anyone is interested here -