In business, you always need room for error.

A safety zone. A buffer.

If you buy and sell a widget, you want to make sure you don’t pay more than you can sell it for.

The rule of thumb is 30%.

If you think you can on-sell a widget for R100, then never pay more than R70.

That buffer will save you from losing money.

If you buy and sell seven R100 widgets at a 30% margin then you will triple your money.

Give yourself a minimum margin of 30%.