Would appreciate your guys advice on this one. I have this salesman that's trying to get me to sell me Schaeffer products for use on our farm. I mean he had some demonstrations and it does seem like a much better product, but costs more than twice what we are paying for oil and grease products now. He said we'd be able to run twice as long change intervals, but when the alternative is half the cost, does that really make it worth it? I'm already doing some pretty long change intervals, generally 300-400 hours and get back goood oil analysis results. On some equipment, I'm already running better than 600 hours with great analysis. Blackstone advises going further on most these but haven't got that far yet. If oil has a decent additvie package that can hold together, seems like most engine wear comes from contaminants more than anything else. Currently we're running Service Pro 15w-40 CI-4 Plus.