Blood is mostly made up of water, as are our organs and muscles. To read specifically about edema, swelling caused by fluid retention where excess fluid is trapped in the body's tissues, see our article Edema: Causes, Symptoms and Treatments.
If you use the Amsoil Ea15K01 and the ASM oil (For 3rd gen Prius), then you can safely go 15,000 miles between oil changes. I drive 25,000 miles per year in my Prius. Amsoil backs up their products by a written warranty.
Our recommendation: Differential oil should be changed every 30,000 to 50,000 miles. You should aim to have the gear oil changed every 30,000 miles, but itâs a good idea to have a mechanic check the differential oil during regular maintenance services.