An airfoil for a blade or nozzle (112, 122) of a turbomachine, the airfoil comprising: an airfoil body including at least one first coolant passage (145, 145A, 210), and an edge opening (220, 220A) in a leading edge (150, 204) or a trailing edge (152, 206) of the airfoil body, the edge opening (220, 220A) having an edge coupon retention member seat in or on an inner surface (172, 272) of the at least one first coolant passage (145, 145A, 210) of the airfoil body; and an edge coupon (198, 198A) having a shape at least partially configured for coupling to the edge opening (220, 220A) in the airfoil body, the edge (150, 204) coupon including: an edge coupon body, at least one second coolant passage in the edge coupon body configured for fluid communication with the at least one first coolant passage (145, 145A, 210) in the airfoil body, and a retention member extending from the edge coupon body into an interior of the at least one first coolant passage (145, 145A, 210) of the airfoil body for coupling to the edge coupon retention member seat in the airfoil body, wherein the retention member seat includes a first retention member seat (170, 270A) at a first axial depth position relative to the leading edge (150, 204) or the trailing edge (152, 206) of the airfoil body, and a second retention member seat (170, 170B, 270B) at a second, different axial depth position relative to the leading edge (150, 204) or the trailing edge (152, 206) of the airfoil body, wherein the edge coupon may be removed by cutting out the edge coupon, thereby enlarging the edge opening to form a new edge opening, thereby removing first retention member seat and leaving the second retention member seat, such that a further edge coupon may subsequently be coupled to airfoil body (124, 130), by coupling a retention member of the further edge coupon to the second retention member seat. an airfoil body including at least one first coolant passage (145, 145A, 210), and an edge opening (220, 220A) in a leading edge (150, 204) or a trailing edge (152, 206) of the airfoil body, the edge opening (220, 220A) having an edge coupon retention member seat in or on an inner surface (172, 272) of the at least one first coolant passage (145, 145A, 210) of the airfoil body; and an edge coupon (198, 198A) having a shape at least partially configured for coupling to the edge opening (220, 220A) in the airfoil body, the edge (150, 204) coupon including: an edge coupon body, at least one second coolant passage in the edge coupon body configured for fluid communication with the at least one first coolant passage (145, 145A, 210) in the airfoil body, and a retention member extending from the edge coupon body into an interior of the at least one first coolant passage (145, 145A, 210) of the airfoil body for coupling to the edge coupon retention member seat in the airfoil body, wherein the retention member seat includes a first retention member seat (170, 270A) at a first axial depth position relative to the leading edge (150, 204) or the trailing edge (152, 206) of the airfoil body, and a second retention member seat (170, 170B, 270B) at a second, different axial depth position relative to the leading edge (150, 204) or the trailing edge (152, 206) of the airfoil body, wherein the edge coupon may be removed by cutting out the edge coupon, thereby enlarging the edge opening to form a new edge opening, thereby removing first retention member seat and leaving the second retention member seat, such that a further edge coupon may subsequently be coupled to airfoil body (124, 130), by coupling a retention member of the further edge coupon to the second retention member seat. an edge coupon body, at least one second coolant passage in the edge coupon body configured for fluid communication with the at least one first coolant passage (145, 145A, 210) in the airfoil body, and a retention member extending from the edge coupon body into an interior of the at least one first coolant passage (145, 145A, 210) of the airfoil body for coupling to the edge coupon retention member seat in the airfoil body, wherein the retention member seat includes a first retention member seat (170, 270A) at a first axial depth position relative to the leading edge (150, 204) or the trailing edge (152, 206) of the airfoil body, and a second retention member seat (170, 170B, 270B) at a second, different axial depth position relative to the leading edge (150, 204) or the trailing edge (152, 206) of the airfoil body, wherein the edge coupon may be removed by cutting out the edge coupon, thereby enlarging the edge opening to form a new edge opening, thereby removing first retention member seat and leaving the second retention member seat, such that a further edge coupon may subsequently be coupled to airfoil body (124, 130), by coupling a retention member of the further edge coupon to the second retention member seat.