Do you use an 'age' rule of thumb when buying in Chicago?

[Sebastien Beauboeuf]

Planning on buying and holding a 2 to 4 unit next year and house hack on the North side of Chicago for my first deal. I realized that most of the buildings I've looked at have garden/basement/in-law units (so below ground). A lot of them are more than 100 years old. Obviously the older the building, the more risk it has and the sooner I'll have to worry about CapEx expenses. With those below ground units and the kind of weather we get in Chicago, I immediately start thinking about foundation issues, pipe leaks, old wiring, etc. I guess i'm wondering if you guys use some kind of rule for the age of the building if you're planning on holding it long term. 100 years or less? 50 years or less? Or nothing more than 30 years old?