I am an auto-electrician and as well as having customers, they have vehicles and may have more than one. It would be good to have the ability to have another tab "invoices", "customers", "vehicles" where I can store information on vehicles and link them to customers and then invoices.
I say "vehicles" but this would Ideally be a dynamic database where users could create their own fields - as you are not to know what information a user of differing industries deems relavent to store. It could be used for other purposes then and applicable to all (if required). example: A letting agency could create a property tab and store property details and then link it to a customer. A customer may rent many properties or a property may be rented to many customers (i.e. student accomodation). example2: my tab would be "Vehicles" and I can store vehicles in kashflow and link them to customers and then invoices.
You could then look up invoices for a particular vehicle, property or whatever subject you have setup. Being dynamic the user can change this tab to say whatever is relevant to their business and also collect their relevant information/fields for that database