Any car whether second hand or brand new can have faults and there are some areas that are more common than others to go wrong, here are some of the most common faults:-
Battery – A good car battery should last upward of 5 years if they are not misused however the reality is that the RAC alone attend over 500,000 battery related incidents each year, and this is mostly down to human error. Leaving headlights on is a common reason for batteries to run flat however cold weather can also affect them as well as only doing short trips in the car on a regular basis.
Car electrics (sunroof, windows, mirrors etc) – these very commonly do go wrong due to car vibrations loosening the wire connections and fuses going. Although a common fault they are not usually too costly to fix.
Suspension – this fault is often caused by poor road condition and can actually write off your car!