What is the ruling on one who performs a charitable act or spends on their family spontaneously without prior intention, and is it necessary for them to form the intention before every act?

It is required to bring to mind the intention of seeking reward from Allah (ihtisab) when commencing any act of worship or permissible deed. It is sufficient to bring this intention to mind for a single type of expenditure or good deed, and it is not obligatory to specify an intention for every single expenditure or good deed, although doing so is better. Some scholars hold the view that the intention of ihtisab at the beginning of the day suffices for all deeds, even if the intention is not brought to mind when performing them, with the caveat that remembering the intention at the time of the deed and its accompanying the deed is better.