I try to find time for 45 - 60 minutes, 2 - 3 times a week for resistance training, where I follow a circuit-training routine. Sometimes, I don't manage, but would manage to squeeze a short one of say 15 minutes. My main aim is to get bigger arms rather than strength (forearms, biceps, triceps, ...) - Does it make sense that if I don't manage to find time for the full circuit, I do 3 - 4 of the circuit exercises which focus mainly on the arms? In general, I tend to build up quite well in chest, shoulders and legs area, however I've never seen a good noticeable increase in arm size, and would like to know if it makes sense that if rather than skipping it when I don't have time, I try to fit in just a few exercises.
Any general suggestions how to get the best of your time at the gym would be greatly appreciated!