They will plug too fast and it is overkill. If a tractor is not used very much, say just for shows, I would consider changing oil each year and filter every other time to limit the amount of big particles getting through. It is a little expensive for us commoners but might be useful in some cases. The oil is sampled and sent to a lab. They can test it for metal content and for Ph and lubricity.
More money buys more detail.
A better use would be to assess the state of an engine that is in question. OK, you bought a good one but they didn't change oil often enough. There is a problem and you will have to decide whether to find it now or wait for it to get severe. The problem is getting worse, fix it now. The second section was authored by Ed Hackett, and is version 1.2 of his OIL FAQ as posted to Usenet.