Yes.

Do I under stand that this is your third year with the same potting soil? I don't think that the typical potting medium would have much structure left after all of that time. One of the most important qualities for a container medium is porosity. This is achieved via the large pore spaces provided by coarse textured materials.

Using potting medium over and over is certainly not something I recommend, speaking in regards to plant roots and plant vigor.

Reusing IN CONTAINERS? I dunno. I bow to Rhizo's experience. As soon as it gets out of the ground- I'm useless.

This is the second year using this soil. I will be using the soil in containers again. I have mixed this soil with a bag of new potting soil, a little bit of composted manure and some vermiculite. It looks pretty good to me. But I guess I should test the drainage.
Diane

I do what you do, reuse potting soil again and again. The organic matter does break down, but the vermiculite and the perlite remain reasonably intact, which gives the porosity. I find it easiest to dump all my old containers out on a cement patio, shake the soil off the old roots, throw in half as much, volume wise, of finished compost, maybe a new bag of potting soil, shovel it all up to mix it, and then refill the containers up to the brim, as it settles down a bit.

I do about what David described - dump all together and add fresh compost, some fresh potting soil, some new perlite, etc. and reuse the 2nd year. But we have a lot of lime in our water and so after that I till it all into a garden bed or the compost piles. You can really begin to see and feel the difference in color and texture after 2 years use with mine.

Having worked for a nursery, I can tell you that every piece of this earth can be recycled as long as you add back to those piles the things that the old plants have used. The old roots will compost, they need extra time to do so, you add back rich earthy products. I had a lady that trained me many years ago to use equal parts of the following: potting soil(does not matter what brand, this is the cheap part)vermiculite/and or perilite,peat. Stir equal parts in a large trach barrel adding water as needed. That was the beginning soil for any time we 'potted up'and we usually potted up several hundred.. Same thing holds true for containers plants. They have the same basic needs.

I've reused the same "soil" for 20+ years, adding fresh peat, fresh bagged potting mix, and fresh fertilizer every year to get enough volume. Works great for me. I save my compost to improve my in-ground gardens and houseplants.