You’re meant to replace the water daily. Not sure how many follow that guideline.
So I don't think the science backs this up.
Make tea such that you enjoy it. Same as coffee.
That's BS. It's true: people do have different tastes and preferences, so opinions are just that. But it's not "superstition": different brands/blends of tea really do taste different, many times remarkably so. It's just like a McDonald's burger vs. a burger from a high-end restaurant. One of course isn't objectively better than the other (from a taste standpoint; I'm ignoring nutrition here), since it's a matter of opinion, but you will find that significant groups of people who like a particular food enough to have tried different varieties will usually form similar opinions, or at least sort themselves into different camps.
"Superstition" implies that the differences people taste are not real, and this is quite simply false. The differences are real; it's up to you which one you like better. More expensive doesn't always mean better-tasting.
If you've a specialty tea shop nearby, that's all but certainly better, though it can be pricey.
You'll find there's a whole new world out there, and may regret discovering a taste for real whole-leaf teas.
Greens, whites, blacks, fermented, oolongs, darjeelings, matcha, gunpowder, pu'er, etc.
There are also herbal teas, such as rooibos, not made from sinchilla (tea plant), but also tasty.
https://insinkerator.emerson.com/en-us/shop/insinkerator/ins...
Always use freshly drawn (filtered if possible) cold water in the kettle. Tea loves oxygen as it helps the flavour develop.
Most of us are guilty of the following... looking at the kettle seeing there is some old, used water in there and simply re-boiling.
If you keep re-boiling the water in the kettle, it loses all of its oxygen and you’ll be left with a really flat cup of tea.
If you boil the kettle with fresh water, you’ll have a delicious cup of oxygenated tea that tastes divine.
https://twinings.co.uk/blogs/news/how-to-make-a-cup-of-tea-p...
I'm not sure how much difference this makes, but when I use the hot water boiler at work, the tea definitely tastes slightly off compared to using a kettle at home. But it's also possible the hot water boiler at work is not producing hot enough water.