Well, perhaps using the example of VW will illustrate. Writeups for the VW Jetta are very good (Edmunds.com) etc. However, back end, indicates a high % of problems: such as 1.8, 2.0 oil burning, etc. etc. It has also consistently been on the 5 worst car's list. However, if you get a TDI which is like 6% of the VW JETTA population in the USA, the diesel engine is not at all known for burning oil! So just that fact alone will bypass a huge structural problem. Which is only one major reason why I recommended against a gasser VW. Also against a 2.0 there is roughly a 1-1.3k premium for a TDI engine but against a 1.8 T there is virtually no premium. So to pay a premium for a gasser than has a high % of oil burners is a risk I would not like to take and to have to pay for the increased risk to boot!!??
Conversely for me, I do not have any 1.8 or 2.0 VW Jetta oil burning problems, for I obviously have a non oil burning TDI engine. The other nit noy stuff I can live with; such as shock absorbers NG at 25k-35k, Rear brakes pads and rotors that are NG at 25k-50k. Excessive right front tire wear. The other warranty stuff will hopefully surface within the 4 year or 50,000 mile warranty period. Keep in mind that in Germany the VW Jetta has a one year/12,000 mile warranty. So the implication is that consistent maintenance is a must/given. This is not the expectation here in the states. Hence the poor reliability rating here in the states.
( I am used to 100k mile shock absorbers in a TLC) plus the fact that struts and shocks for a VW cost MORE than Bilstein shocks for a TLC)
So in the ultimate scheme of things this particular product, this 2003 VW Jetta is expected to function as my commute rig, to get 45/49 mpg, with 25-36k year miles and go 550,000 miles with expected scheduled maintenance and hopefully low unscheduled maintenance at roughly 6-7 cents per mile operating costs. So far, its a keeper. Would it be good for her? Given her need to do 7k per year, etc, I doubt it!
Another thing to keep in mind, in the past, I have run a used 1970 VW Beetle 250,000 miles, which was purchased used in 1971 for 1,800 dollars and sold in 1978 for 900 dollars. My perception is that this 2003 VW Jetta is better engineered. So to me the 500,000-550,000 seems infinitely do able.
So the procedure to evaluate, variants of the Toyota and such, should be roughly the same. Obviously each OEM and model will have its specific issues.