Dont go for the armor. There is a limit to what free players or normal spenders can attain in armor. never spend on medium thread since advanced threads are more rare and hard to come by. So even if you rush now to improve battle armor you will be stuck when you will start needing advanced thread since for normal players the only way to get them is events(which are rare) and space time shop( you may get 4-5 threads per space time season. Its better to slowly collect threads from monthly mission and SA, and slowly level up armor while you keep stacking on advanced thread. Its better to spend the coupons on other powering up elemeents rather than threads as far i have seen.

Edit: Big mike was talking about clothing as armor. This is my perspective on general strategy regarding normal armor.

Oops..you are right..reading again..thats correct..my bad.Sorry...still its a fact about armor