Drake, of Give Me Indiana, asks:
These are all very good questions, and very important things to know if you are going to buy any jacket. As a rule of thumb it is always better to be long than short, because any measurement that is too short you may or may not have the fabric available to lengthen that part of the jacket. It cost me quite a bit of money to learn that one. You can be long on any measurement by a quarter to half in or so without really affecting the look and fit of the jacket. On ebay you don't always know if the person knows the right place to measure and if they are rounding up or down. I have purchased many suits on ebay that say they are my size only to find out they were way off. I only buy from an ebayer that isn't a large store operation since it's easier and more likely that you can get the person to confirm those measurements for you and give you any extras you might need.I have begun searching for suits and sport coats on eBay and thrift stores. My question for you is how specific should I be in measurements, and what measurements are the most important or hardest to alter? I know my measurements, chest, sleeve, etc. and I plan to take the item to a tailor after buying, but I need to know where I can be off on the original measurements as I can never find something that fits perfectly. How close should sleeves be? Is it better to be too long or too short. Is it possible to add or remove inches across the back if the jacket is too tight? Any advice you could give on thrifting or eBay adventures would be appreciated. Thank you.
Knowing your exact measurements (even to the quarter inch) are always the best since you have a realistic image of what kind of jacket will fit you. The hardest elements to alter are the shoulders and the length of the jacket, getting these right is imperative.
You can alter the shoulders but it is a very risky and costly procedure that should only be undertaken if absolutely necessary (like if it was your grandfather's jacket and you really want to wear it, etc.). You can be off a little bit here without really affecting the look of the jacket, and it's better to be a little too long (but only by a quarter to half inch) so it doesn't look like your jacket shrank on you.
Same thing on the sleeves, you can be long by a quarter to half inch without affecting the look too much, if you're a stickler for how much shirt cuff you like to show it's much easier to shorten it a bit.
When you say the back is too tight, I'm guessing you are referring to how it fits across your shoulder blades. If the jacket is fully lined, you may be able to feel how much extra fabric is underneath the top of the back, but undoing the lining is the only way to tell for sure (which should only be done by a tailor). It may be possible to let it out a little bit, but there usually isn't too much room for letting out in this area. However, if the shoulder measurements are right, you shouldn't have a problem here.
The length of the overall jacket is also important because most companies are not the same in their S/R/L measurements. I'm a 40XL, but usually a 40L will suffice as well. Know your desired length from the nape of your neck to just under your rear and go by that instead of tagged size. Again, better to be slightly long on the length, unless you like the Thom Browne look. If the jacket is well tailored or just naturally fits well, the extra length will not really show.
Chest is also important, but only to a degree, since jacket darts can be taken in, and the waist can be taken in from the middle of the back to minimize the bulkiness of an ill fitting jacket and give it that nice slimming nipped waist look. Fortunately, getting the chest right is fairly easy. You don't want a skin tight fit, so give yourself an inch or so on top of your real chest measurements to account for shirts, sweaters, etc. This means that when you put on the jacket, fasten the proper button and pull it away from you, it shouldn't separate by more than an inch or two.
When I go thrifting I not only try on the jacket but measure it as well to make sure I'm not just excited to find a really great jacket and trying to convince myself that it fits.