I can't reply to everyone so thanks to you for your replies. My take is that for simple stuff I don't need classes. An example is I'm writing a simple GUI calc

I can't reply to everyone so thanks to you for your replies. My take is that for simple stuff I don't need classes. An example is I'm writing a simple GUI calculator for my brother who's a stone mason. It's a stone calculator that accepts quality, height, width, length measurements in mm and output a tables with volume costs in either metres or feet cubed. I could model it as a job classes that accepts a stone list class, and customer name, cubed cost, tax, parameters. And methods to get total costs, taxes etc. The stone list class is a list of stone classes. Each stone class has quality, height, width, length parameters and methods to get cost, get taxes, etc. But all I do is store the measurements in a list, each list (stone) is stored in another list, and I iterate. Calculations are done on adding a stone, or when you recalculate the whole list. I know it's not big, complicated, or impressive example but for me it was easier to implement it classless.