Which articles of clothing does one make a ‘shecheyanu’ on?
Or is it anything that makes him happy?
One only makes shehecheyanu on a garment that has a degree of importance. However, it does not have to be a very special garment, such as a suit, and if a person experiences joy in buying a nice (but not a very simple) shirt, he should say shehecheyanu.
Authorities dispute whether the berachah of shehecheyahu is entirely subjective, depending on the subjective joy a person feels, or whether the berachah includes an objective element, whereby if a garment or item is not important, and does not usually induce joy, one cannot recite the blessing.
According to the Rosh, the Radvaz, and the Shulchan Aruch (223:6), a poor person, who experiences joy in purchasing simple items like shoes and socks, should make the blessing.
However, according to Tosafos (Berachos 59b) it appears that one does not make shehecheyahu on something that is not objectively important, and this is the opinion of many poskim, including the Terumas Hadeshen and the Rema (223:6), the Rema adding that this is the custom. This ruling is also stated in the Mishnah Berurah (223:24).
However, this does not mean that one can only make a shehecheyanu on a very important item of clothing, that everybody will experience joy from. Even if the item has some degree of importance, such as a fancy shirt, it is sufficient for making the blessing, provided that the person experiences subjective joy in buying it. Only on clearly unimportant clothes, such as socks and underwear, or simple shirts and the like, would one not make the blessing even when experiencing subjective joy (instead, one should thank Hashem in one’s own words, or say the blessing without mentioned the Name of Hashem).