Frequency of oil change in Cadillac Deville 1997?

ON A 1997, I WOULD CHANGE THE OIL @ FILTER AT 3,000 MILES. I NEVER EXCEED THAT AND NORMALLY CHANGE MINE BETWEEN, 2,500-3,000. MY LAST CAR, A 1994 CAMRY , HAD 205,000 ON IT . I BOUGHT IT USED WITH 73,000. AN ENGINE COSTS SEVERAL THOUSAND DOLLARS. CHEAPER TO MAINTAIN YOUR CAR. EVERY CAR I EVER HAD,( 10 ) SINCE 1963, HAD AT LEAST 100,000. + MILES ON THEM.