存储对象数组或在需要时创建？

I'm new to objective-c and ios, but I'm coming along alright. Now I've run into a situation where I can see two ways of arriving at the same destination. I'm just curious as to which way would better suit the efficiency of the program. I apologize in advance if there are better ways of phrasing all this that I don't know of yet.I'm new to objective-c and ios, but I'm coming