Will: Wills make frequent appearances in the series:
As noted above, Dimity's will and its fulfilment supply most of the plot for the first novel.
The Willis' family law firm frequently deals with wills. This often justifies Bill's absences from some of the novels, in whole or in part, while he rewrites wills for fussy clients who find their heirs unacceptable or negotiates disputes between heirs after a will is read. Bill's job also supplies the premise for Aunt Dimity Takes a Holiday.
Will is a disambiguation. A list of tropes about wills can be found in Will and Inheritance Tropes.
"If you aren't him, then you apparently got your brain from the same discount retailer, so..." - Fighteer