Hampers are unopened, firm and small (9)

'hampers' is the definition.
The definition and answer can be both related to change as well as being verbs in their -s form.
Perhaps there's an association between them I don't understand?

'are unopened firm and small' is the wordplay.
'unopened' means to remove the first letter (the opening of the word is removed).
'firm' becomes 'strict' (firm can mean strict or severe).
'and' means one lot of letters go next to another.
'small' becomes 's' (abbreviation - e.g. clothes size).
'are' with its first letter taken away is 're'.
're'+'strict'+'s'='RESTRICTS'

Can you help me to learn more?