Chicago basements deal with heavy spring rain, snowmelt, and clay soil that holds water against foundation walls. Finishing one without addressing moisture first is the most common and most expensive basement mistake.
Before any framing goes up, look for the signs: white mineral deposits on concrete, musty smells, damp spots after a storm, or peeling paint on the walls. Any of these means water is finding its way in.
The fix depends on the source. Sometimes it's as simple as redirecting downspouts and sealing cracks. Other times walls and floors need a waterproofing system before they're covered. Either way, it's far cheaper to do before drywall than after.
Once the space is dry, material choices matter. Vinyl plank flooring handles humidity better than laminate or carpet, and leaving a small gap at the bottom of the drywall helps prevent wicking. Done in that order, a basement becomes real living space rather than a storage problem.