Q.Soil In Potted Veggies
I plant my garden (many veggies and herbs–tomatoes, squash, beans, etc. ) in large planters. My husband takes topsoil off every spring to add new potting soil to remaining bottom half soil. He mixes it all around and we add garden tone and our compost to it. Do we need to do this every season, or can we just take out any old roots and then add garden tone-compost to the old soil for maybe 2 years worth? It is very costly to add new soil to half of old soil. I have 40 planters in our garden. Not to mention it is hard work for my husband to take out half of the old then mix the new to it.

Certified GKH Gardening Expert
As long as the soil is healthy, this should be okay. You may also want to consider sterilizing the soil before replanting. This article will help with that: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/sterilizing-soil.htm