Age or mileage ?

What manufacturer?...Ford, GM, Dodge, Toyota..
What motor?
Gas or Diesel?

Infiniti. 5.6 L gas engine .... And no giggling , I am learning all of this ....

The 2004 with 50K would interest me more than the other two unless they were DP.
Ford,GM ????

Sorry Infiniti is apparently made by Nissan ..

Not sure about your 5.6L engine, but my 2004 4.5L Infiniti FX calls for plug replacement at 100k miles which requires removing the valve covers.
Just me but lower mileage on a gasser is the way I'd lean.

It's really about maintenance and care.
You could have two 2010 infiniti models equipped the same and driven the same number of miles, one would be great the other no so great. The great one was well maintained and driven with care the other was beat to death, not maintained properly, but looks as good as the great one.

I would have a mechanic look over two and choose the one with the best results.

.

Age is more of a factor at 10 years I think.

thedon42 wrote:
Infiniti. 5.6 L gas engine

None for RVing.

If you insist, then it doesn't matter much. Its the same design, same engine/trans. Pick the better maintained one, best color, etc.

More information is needed. As a graduate of the School of Hard Knocks, I can say from experience that 90,000 highway miles over 3 years is much less wear and tear than 50,000 city miles over 10 years, if that is the scenario.