everything I've heard says new dirt every year. I suppose you could mix it 50-50 with finished compost and do ok.

Tomatoes, by the end of the season, can typically suffer from bacterial, tomato spotted, verticillium or Fusarium wilts - spread by fungal spores or insects chewing on the leaves - and that works itself into the soil. And there is no way to fight the bacterial, viral or fungal agent that causes these afflictions.

So I just dump it all into a pile and use it for other pots (greens, flowers, herbs) or in my garden beds.

It isn't a guarantee there would be issues, but certainly a likelihood....I also bleach the pots each year before using them just to be sure.

Go light on the nitrogen or you'll get hedges with small fruits. You can get organic "tomato" food at any garden center and it works well for eggplant and peppers as well. I go heavy on potash with the potatoes. I grow most of mine in-ground and we're always flooded with tomatoes. Even after the stalks die off, the damn things keep producing. The most important thing with container growing them is to avoid keeping the feet wet. That leads to blossom-end rot and overall low productivity. In a well-dug raised bed that is rarely a problem.

I can't say I've had a problem with reusing container soil. You still have to mix in some light fertilizer and top dress periodically throughout the growing season.

I just don't have the space for planting without using containers.

I will follow the advice I have received here.