Conventional motor oil companies recommend 3,000-mile drain intervals:
Conventional 10W-30 Motor Oil (40 quarts needed for 25,000 miles)@ $1.50/qt. x 40 =$60.008
Standard Oil Filters@ $5.00 per filter x 8 = $40.00
TOTAL COST = $100.00

AMSOIL recommends 25,000-mile/1-year drain intervals:
AMSOIL 10W-30 Synthetic Motor Oil (6 quarts needed for 25,000 miles)@ $5.85/qt. x 6 =$35.102
AMSOIL Super Duty Oil Filters@ $10.00 per filter x 2 =$20.00
TOTAL COST = $55.10

You save $44.90 per year using AMSOIL premium quality synthetic motor oil and oil filters.