Every guy should own at least one suit in case of dressy event, wedding or funeral, and if you're a one suit kinda guy you'll want to buy a high quality jacket- so you never have to buy another.
Now unless you can afford a custom tailored suit, or you've got a connect in the garment industry, you'll want to know how to spot a quality garment and make sure you're getting a good deal.
According to this smart graphic by Ted Slampyak and The Art Of Manliness you should start by checking the fabric and stitching, then look for a finer lining, lapels that roll a bit and buttons that aren't made of plastic.
-Via Lifehacker