Unless you are a sample size, most clothing off of the rack will need some sort of tweaking, whether you’re ready to admit it or not. Why do you think store mannequins have a bajillion pins going through their clothing on display? It’s perfectly fine to rock your freshly de-tagged stuff straight out of the store, but if you take it to a proper tailor to tweak the shoulders, hem, etc., you’ll have a better appreciation for what you’ve just bought.