My folks were
Buick lovers also. 1955 century, 1961 wagon, 1965 Sport wagon w/ glass roof, 1967 Electra, 1975 Century custom wagon, 1978 Electra Linmited. The '55, '65, and '75 were bought new. All were kept long term. I learned on the '75, and my brother bought the '78 and drove it until it rusted away.
After my dad retired, he owned a Dodge van, one Ford, and one Pontiac. He said they were all fairly the same by then.
A friend of mine who's dad owned a '65, '69, and a '73 Cadillac stepped down to a Buick in 1980. He said he couldn't see spending over $7,500 for a car.