We all have our favorite teas which we brew more often than any other type of tea. One of my personal favorites is Sencha, a tea I have been brewing almost daily. But I have realized recently that too much practice at brewing a certain tea can build a certain confidence, or lax in attention when brewing that tea compared to a brand new tea.
I have paid for my inattentiveness quite dearly as the last two times I have brewed sencha, thinking of it as just brewing sencha once more, I seem to get the first infusion down pat, but subsequent infusions are often so bitter it might as well be stripping away my tooth enamel. The hardest part about messing up a tea, is getting back on track to great tasting infusions, as the normal rhythm of brewing that tea is thrown off, and I often have a hard time accurately judging what my next brew length should be compared to how long I would normally spend on that infusion number.
I almost feel this is the reason why trying an unusual tea, or a tea for the very first time often leads to better results. It is the focus being strictly on the tea, and not so much on the homework or research, that leads to consistent and good results.