This is a basic guide to buying a high quality suit whether it's from eBay, other online sources, or a brick and mortar retail store. This information is pulled together from books, web forums, and my personal experience.

I will briefly discuss style, fabric, quality construction, and fit/tailoring.

Style

Double Breasted


Double breasted (a large overlap of fabric at the front with two rows of buttons) suits come in and out of fashion. They were quite fashionable in Bogey's time and came back during the mid-80's (almost 30% of suit sales were double breasted) but are currently unfashionable. They will however always be stylish.

The button stance (position of buttons) on a double breasted suit is important. The rows of buttons should be narrow and high. A wide button stance makes the wearer appear stumpy. The suit can have 6 or 4 buttons total with 2 or 1 fastening buttons. It's often said that a 6 button with 1 fastening button elongates the body and gives the illusion of height. 4 button suits were common in the 80's and may look dated today. Bogart is wearing a 6 on 2.

Some things to think about when considering a double breasted suit

Single Breasted

Cary Grant is pictured wearing a 3 button single breasted (slight fabric overlap and one row of buttons) suit. 

Single breasted suits can have as few as 1 button or as many as you like. Any more than 3 buttons should be avoided however. The 2 button and 3 button come in and out of fashion but both are appropriate.

Some considerations

• 3 button elongates the upper body so it works well for shorter men
• 2 button breaks up the large expanse of fabric across the chest and shows more of your shirt and tie, great for taller men
  
• a 3 button where the lapel rolls over the top buttonhole (3 roll 2) is a nice distinctive look
• the gorge (widest point of lapel) should be high to avoid looking dated
• never button the bottom button
• one buttons are inappropriate for conservative business but can look sharp
  

Fabric

Super what?
The super wool designations (e.g., Super 100's) are based the number of spools that can be spun from 1 pound of that wool. Developments in sheep breeding and wool spinning/weaving led to finer and finer wool. When the wool count hit 100 spools/pound, the marketers sold it as Super 100's.

A higher Super number is not necessarily better because finer wools are unavoidably more delicate. There are other factors to consider when judging wool quality. Super 120's or 130's are soft but robust enough for everyday wear. Going into the 150's or 180's, durability can be a real issue. You might consider saving these super soft fabrics for a suit worn on special occasions.

Wool, mohair, cotton, linen, silk, bamboo (!)
There are so many materials a suit can be made from I will just say that you should buy natural materials. No polyester please. Wool is the standard. If you have the money, buy cashmere or even better, Vicuna. Some mohair (20-30%) blended with the wool will give the suit a sheen. Silk adds a certain softness and sheen to the garment but it is thought to wear hot. Cotton, linen (also called flax), and others are probably best for casual wear.

Hand, Heft, Hue
The feel of a fabric is referred to as the "hand." How does it feel in your hand. Is it soft and rich. Does it bounce back when you crush it. Is the weight of the fabric appropriate for your climate. Wools are rated by ounces. A 12 ounce wool might not be great for Southern California. In today's climate controlled environments, there are some more traditional men who prefer a heavier wool because of the way it drapes. I assume you're reading this as part of a beginning to building your wardrobe. That means charcoal and navy. Think of the uniforms during the Civil War to help you remember - grey and blue. Solid charcoal and navy are your staples along with subtly striped charcoal and navy. What about black? It's not ideal for daytime wear other than a funeral. I would hold off on black until you have charcoal (a good stand in for black at a funeral), navy, some stripes or other patterns (windowpane, Prince of Wales, etc) in other colors covered.

Construction

It's easy to get suckered by a fancy label or advertising. A high price doesn't necessarily equate high quality.

Canvas
The canvas is the interlining of the jacket. It lies between the outer fabric and inner liner and gives a jacket it's shape and structure (so that it doesn't look like a shirt or sweater). There are two basic methods for constructing this - fusing or stitching.

Fusing is an inexpensive way of gluing the "canvas" to the outer fabric. This leads to a jacket that is a bit stiffer and doesn't conform to your body as well as a stitched canvas. The glue can also break down over time especially with harsh dry cleaning. This leads to irreparable bubbling up of the fabric from the canvas. I haven't owned a fused suit long enough for this to be a problem but the fit of a fused suit is noticeably poorer to me and I would always recommend a full canvas jacket.

To test for a stitched canvas, "pinch" the jacket just below the bottom front buttonhole. See if you can feel a loose layer in between the liner and the outer fabric. That's a stitched canvas. If you only feel two layers, it's fused. There are some half canvas jackets to confuse us more (Ralph Lauren Polo "blue label" for instance) but I won't get into that.

Handwork
You'll sometimes hear sales associates tell you that their $1500 suit is "almost entirely handmade." Take that with a grain of salt. If they mean made by human hands on a sewing machine than I'm sure it is "handmade" like any other item of clothing. But don't believe that it's made mostly by hand using needle and thread. There are 1400 hand stitches in a $1300+ Hickey Freeman mainline suit. There are almost that many in just the lapel of an Oxxford costing a few times more. And that's still short of the thousands of stitches in a bespoke handtailored suit.

This is one area where you will have to do some research online because it's hard to tell from looking. A machine stitched collar or buttonhole is easy enough to spot but the rest can be difficult.

General considerations

• full canvas or bust
• everyone automatically thinks of Armani but Armani is overrated and overpriced - a $1900 Armani Collezioni will be fused
• same for suits by fashion houses that earned their name in women's couture (Gucci, Prada, etc)
• in no particular order, high quality ready to wear suits can be made by Belvest, Isaia, Zegna, Canali, Corneliani, Raph Lauren Purple Label, Brioni, Kiton, Oxxford, Brooks Brothers Golden Fleece, Attolini, Pal Zileri, Luciano Barbera, etc.
• each label may have multiple lines that are of varying quality and some sell their fabrics or make suits for other labels. A bit confusing but don't buy an inferior no name suit that is using Zegna fabric but without any of the Zegna build quality
  

Overall, I would recommend looking for labels like Canali, Corneliani, and Isaia because they can be had for quite cheap from the right source. Hickey Freeman is a great value and can be found heavily discounted at a number of places (< $300 or less).

Fit

There are a ton of articles online about this so I will just reiterate that most men are wearing their suits too big. Big padded shoulders, boxy body, long sleeves threatening to swallow the hand, long jackets, big baggy pants pooling at the feet. It looks bad.

Make sure you're wearing the right size! Did the sales associate actually measure your chest or did he look at you and say, "Ehh you look like a 40R." That's what they say to just about everybody! Sleeves and pants can be tailored but only if you get the right shoulders and jacket length to begin with.

Well thanks for reading this guide. It's pretty basic but I hope it's helped you a little bit in building your tailored wardrobe.