It depends on your comfort level. The reason why you get an inspector when purchasing a coop or a condo is to try to determine, not only the current physical condition of the unit but also the general condition of the building’s structure, mechanical systems and common area. Problems with any of which, could potentially lead to future increases in monthly common charges/maintenance or assessments. These issues may not come up when reviewing the minutes of the board (if a cooperative) and may not be in the offering plan if not the initial offering from the building’s sponsor. Even then, you never know. If you decide to forego an inspection, assume a worst case scenario when contemplating to buy a unit. Even then, you can never anticipate everything.