This work is concerned with understanding mechanisms contributing to the mechanical durability of adhesively bonded joints. To that end, the response of coupons bonded with brittle and toughened adhesives are compared under quasi-static and repeated load environments. Since this phase of the work considers adhesive response (rather than adherend failure), the adherends are made of 2024-T3 aluminum. The testing regime is designed to study the effects of peel (double cantilever beam coupons) and shear (wide area lap shear coupons and scarf joints) stress on bond strength and durability. The coupons are bonded using brittle and toughened adhesives (FM-300, FM73, EA9696) so that effects of adhesive strength and toughness may be independently considered.