I guess that money bed you have been sleeping on was getting a little firm.Rotella t6. Changed it at 20 miles then 50 miles. At 50 miles I added a gold plug to hope to catch metallic pieces that are magnetic.
I'll change it again at 100 then every hundred to 500. Then every 500 after that. May be overkill to some, but it will make me sleep better. That's all that matters