Prevent broken formulas using tables, validation rules, separate worksheets, named variables, and the power of LAMBDA.
Excel 2007's new table feature eliminates the need to copy formulas; once you define a data range as a table, Excel will do it for you! Tables are new to Excel 2007 ...
Excel table formulas shift from cell positions to named columns with #All-style tags, keeping calculations readable when layouts change.
Excel validation lists avoid blanks and errors with TOCOL(ignore) plus FILTER; the spill range stays stable across worksheets.