I’m a retired CPA-turned software developer, who now teaches classes on retirement planning and investment management. I’m an Intermediate-level Excel user (I would have said advanced before seeing the Tiller code)’ always working on raising my skill level. Studying the Tiller templates gives great examples. The basic platform is very clever - using dedicated sheets with simple tables for input transactions that are downloaded from banks, then using advanced techniques for summarizing and reporting on separate sheets. Using some of these techniques has helped me upgrade some of the many spreadsheets I use for asset allocation, tracking investment portfolios, etc., in addition to my own budgeting process.