Agreed! Totally normal, for a group of frugal financial geeks. I've got linked excel sheets for Budget, Investments and Asset Allocation, Taxes, and Charitable Giving. Admittedly, my Taxes sheet needs some serious work, but for that I need to get a better grasp of Tax law, which I don't find nearly as fun as playing with asset calculators within excel. Other than having fun, the Investment sheet is most practical for calculating what I need to do to rebalance (which I do through investments as I'm in the accumulation phase). It also automatically changes my allocation with my age, as I've determined in my written investment plan.