I use Agenda as a database for all the things that I occasionally need details of and would otherwise never easily find. For example, my categories include: Insurance Policies, Household Purchases, Maintenance and Improvements, Services, Utilities etc.
Projects under each category are a particular product, item or company e.g. Double Glazing, Solar Panels, Electricity, Sky TV., Vodafone, Fridge Freezer, Software Purchased.
A pinned note in each project includes the details of date purchased, customer service phone numbers, warranty details, serial numbers etc. or whatever is appropriate (i.e. static information possibly required when contacting a company by phone, making a claim or whatever). Dated project notes contains dates and details of phone calls, servicing, breakdowns, amendments etc. to each project. This way I can easily refresh my memory on what has been done or said in the past.
Projects where I have been promised a reply or an action I put on the “Agenda Overview” so I don’t forget to chase people up if necessary.
I also have a Birthdays & Anniversaries category and a project for each month and notes under each month for each person.
Obviously, there are many other uses which I will find for Agenda but after only a week’s use I have found it invaluable.