^ I'll go the opposite route, that it's penny wise but pound foolish to buy a set of 4 used tires unless you're soon to sell or scrap it.
They may have abnormal wear. They may be half way through their use-by date. They may have sat around oxidizing the sidewalls because not driven on in a while.
You're (probably) paying for a new alignment and mounting/balancing every time you put tires on, so the cost to years use ratio is often no better for used tires unless the new alternative was something "sportier"/premium than it needed to be, raising the comparison cost.
In other words you can just about drop down a sport level on new tires when comparing performance to older used tires, and with used, you may not have much pick what you end up with that is a good combination of type, age, wear, etc. unless you spend a lot of time on it, a lot of time that has value, vs # of years use before replacement again. New tires just aren't that much of a cost increase as a % of TCO for a vehicle.
As far as which new tires to pick, there are so many options because there are so many different priorities people have. If the current tires are cracking with tread still on them, one thing that doesn't seem important is to get a high mileage rated touring tire, that their primary strength is overcome by their aging from low miles per year, except that many are also low rolling resistance to eek out slightly higher fuel economy, but if not many miles are put on a year, not as much fuel savings.
