I know you can "reuse" a formula by copy/paste to a new cell and the
relative/absolute characteristics of the formula will be preserved. BUt this
means that if the formula needs to change then I have to look for all places
to which it was previously copied and carry out the copy/paste again -
tedious and error prone.

I want to enter a formula once only (eg. in the column heading above where
the formula will be used). Somewhere else in the sheet I want to say "use
the formula provided in cell R,C" and adopt the relative and absolute
references inherent in that formula.

For example ... =USE($H$1) would be a nice function

Can this be done?

An extension of this would be to reuse not only the formula of the referred
cell, but to also reuse some other characteristics of the referred cell

For example ... =USE($H$1,"format"&"conditional format")

Can this be done?