Soil Test are recommended every two years to help us stay on top of changes in the soil of your lawn. It lets us see if lime or gypsum is needed. It helps us see if other nutrients will need to be added. The cost of a soil test is $15. You can tell if its time to check the soil again if you look at the remit slip portion of your invoice that was left on your door. If its empty then yes we need to run test. In most cases it will show the year of the last test taken. If its the second or more years after that then yes we need to run test.