Q? What happens when the person you rely on to look after your large and complex spreadsheets isn't there or has trouble squeezing in further changes? How risky is this weak link for your business?

Models are well organised and largely self-documenting. Entities like departments, customers, products and hierarchies are altered or extended using simple screens. Rules are clearly defined in scripts, not cells, and separated from your data.

Benefit: More flexibility and clear organisation means it's easy to train people for maintenance. You won't be constrained by capacity either.