Depends on what Im looking for. If Im buying a cheap vehicle for a beater or something, I wouldn't think twice about taking something with 100K and putting another 1-200 K on it. But that's cause I would only do the bare minimum needed to keep it running and nothing else. Wouldn't care about body work, worn interior pieces, any other malfunctions that didn't affect drivability.
If this is gonna be my nice around the town car that I'm keeping for awhile and Im spending some real money anyway Id spend a little more and get something under 4 years old, under 40 thousand miles. Don't like idea of buying something for my primary vehicle right when it's time to replace expensive parts, or that only has 1/2 or 1/3rd it's life left. Id only chance a high mileage used vehicle as a VERY cheap spare I dont care about so that if it croaks early, so be it.
ID rather spend a few thousand dollars more up front than at the repair shop. Think about it: If youre trading in a 150000 mile car will you be worried about things like fresh tires, brakes, coolant flush, amd transmission flush, etc... in that last month or two before it's gone?