I have gardened for many years, including tomatoes, but never thought of saving tomato seeds or letting them come back next year. I know nothing about this, and wondered if I just let the plant totally die back, will the tomato automatically come back in the spring. The tomato plants were pretty much bought up when I got to the green house, so I grabbed a "Cherokee Purple". I hope this will happen, as collecting the tomato seeds to replant seems daunting to me. Thank-you.
The tomato plant will die completely in the winter, however, if there are seeds that have dropped, you could easily see some new, volunteer plants in the spring. Here are some articles that may be of interest you: