How to determine if tea has expired?

The green leaves are interspersed with silver-white hairs, resembling a flower, and when brewed, the green leaves hold the buds as if they were buds in their first blossom, hence the name White Peony:
①Appearance:
Tea colour: Whether the colour of the tea leaves changes, such as from bright green to dark, from black to grey.
Tea leaf form: whether there is mould, lumps, insects, deterioration and other phenomena.
②Aroma:
Fresh tea leaves usually have a clean, floral or other natural aroma.Expired teas may have a stale, musty or other unusual odour.
③Taste:
Taste the tea after brewing to see if the tea broth retains its original flavour, and whether it appears to have a strange, musty or sour taste.
④Colour of tea broth:
Observe whether the colour of the tea broth changes, such as whether the green tea changes from bright green to brown, and whether the black tea changes from red to dark.
⑤Dryness of tea leaves:
Whether the tea leaves are still dry or not, if the tea leaves are damp and mouldy, it is likely to have spoiled.