Most, but not all, operate 24 hours. Some stations close at night. Late-night CTA travel is generally not advisable. North and south bound buses generally stop at every other corner. East and west bound buses generally stop at each corner.
Exact change is required on buses.
For frequent travelers an easy way to pay for public transportation is a plastic transit card which can be purchased from vending machines at CTA stations and other locations. These cards can be used to pay your fares. There is no extra baggage charge.