I don’t believe in teaching 10% tithing because I have come to understand that the people most susceptible to its teaching can least afford the financial burden and those who have the most capacity for following it are the least likely to meet it when in actuality they should be exceeding it. 
So where are we with counting the cost and saving all we can? Wesley comes down hard on people’s vanity in this section. Don’t buy stuff for the sake of pride. No keeping up with the Joneses - it’ll just leave us bitter and empty - not to mention potentially broke. Wesley invites us to keep it simple and to teach our children the same.
So what does John Wesley have to say about earning all we can? If I were to sum it up, it would be something like this: work hard, find the thing that you can do, do it well and with honesty and integrity. Don't take a job that makes you sacrifice your morals. Nothing that hurts other people or forces you to lie, cheat, or abuse anyone. Work hard but not so hard that your body breaks. Make sure that you can rest - remember that we need Sabbath rest - and that the labor doesn't literally kill you. The same goes with your mind. Make sure that you have time to rejuvenate. Make sure that you have time for your family and community, because that's part of our life's work.