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Irregular stitching generally indicates high quality.  Machine sewn fabrics will have uniform stitch lines.  Inspect the seam running down the side of the shirt. A high-quality garment has only one line of stitching visible on the side seam, while most shirts have two visible rows of stitches.  Also check whether or not the stitches are uniformly distant from one another, or the pattern is irregular. Another thing to check are the buttons running down the front of the shirt.  Generally speaking, buttons sewn on by a machine will be loose, or some of the thread might already be coming undone.  Another thing to check is the button holes themselves.  Make sure the stitching of the button holes are bound tightly together. In each case, use your fingers to grab at the stitch line of the shirt, or one of the buttons/button holes.  Gently tug, twist, and move it up and down.  If you already feel as if the stitches are about to come undone, or that they are loose, you will want to stay away from that shirt. This button is usually not there in lesser quality shirts.  The gauntlet button allows for the use of less fabric, and a tighter fit for a person wearing the shirt.  Gauntlet buttons make it easier for you to roll up/down your sleeves when you feel it is appropriate.  Shirts with gauntlet buttons would be great to wear on a hot summer day, where you can roll the sleeves up and enjoy the outdoors more comfortably. Cheaper, or lesser quality shirts might have the gap in fabric, but no gauntlet button.  If you cannot afford a higher priced shirt, you can always attach a simple basic button to the area where the gauntlet button should be. How to Sew a Button "  The yoke of the shirt is the panel of fabric which runs along the back of your shirt, near your shoulders.  A "split yoke" will have two pieces of fabric sewn together on an angle, rather than one singular piece of fabric.  Turn your shirt around so you are looking at the back of it.  At, or near, the shoulder area you should find a rectangular shape of fabric stitched into the shirt.  If the center of this piece of fabric has stitching, and comes upward at an angle, your shirt has a "split yoke." The "split yoke" shirt design shows a level of higher quality.  If your shirt is striped, there is an added benefit to having a "split yoke" shirt: the stripes will run parallel to the "yoke" seam, creating a more crisp look. "Split yoke" shirts also give the person more room to move around in.  This is because the stretches more length wise, towards your shoulders. Ply count is how many different yarns are sewn together to make the threads used for the shirt fabric.  This can sometimes be found on the shirt label.  Single-ply shirts are more softer textured and delicate.  Two-ply shirts are more tough, but weigh more. Thread count (amount of threads per square inch) is also important.  For example, if you buy a two-ply shirt, you will want around a 120 thread count.  When the thread count starts to rise, especially for two and three-ply shirts, the shirt can become bulky, and uncomfortable.  This can be found simply by looking on the tag of the shirt, or asking a clothing professional in a store. Single-ply shirts are great for more moderate, to warm temperate zones.  Two-ply shirts are generally better for breezier, and colder areas.  Finer dress shirts are made of two-ply instead of single-ply. Shirts that are wrinkle-free, perspiration proof, shrinkage free, or water resistant are all laced with special chemical agents (see the next step for potential allergic reactions).  Each of these can change the quality and feel of the shirt.  Check the tag of the shirt to see whether there is a notice about any added chemicals, or special ability (such as water resistant) of the shirt.  If the tag does not contain this information, make sure to check with a clothing professional before you buy the shirt. Wrinkle-free shirts have a mixed record when it comes to actually being wrinkle-free.  While in general the wrinkle-free shirts do have less wrinkles in them, the shirts are looser around the body.  This is because the chemical agent added to the shirt changes the nature of the fabric.  Shirts that do not contain this chemical are better suited for business jobs, as they fit better, and present a more crisp look.  Wrinkle-free clothes are better for a more casual setting.  Perspiration proof, water resistant, and shrinkage free shirts also contain chemicals which alter the fabric of the shirt.  Once more, there also mixed reports about their ability to combat such problems.  The only way to find out if they actually work is to test them.  Working out in them, spilling water on them, or washing them can tell whether the shirts are what they claim to be. Chemicals, added agents, or fabrics made with two or more different cloths can sometimes cause people to have an allergic reaction.  Sometimes this information is added to the tag of the shirt, but you should also ask a professional.  Check with your doctor that your list of known allergens that you have bad reactions to is up to date.  Ask your doctor whether he or she has any advice/medical fix to your allergies. Any shirt that is created with a synthetic fabric can be laced with chemicals and dyes that are impossible to wash out.  Almost all dress shirts are treated with some type of chemical before they are shipped out of the factory.  Wrinkle-free, perspiration proof, and anti-shrinkage shirts all have the potential to contain some sort of chemical or dye.  Make sure to check the tag on the shirt, and ask a professional for help.  Beyond asking a clothing professional for help, you can do some things on your own to check.  Make sure to smell the shirt before you buy it.  Sometimes shirts can get mixed up, or thrown in with other items that might be harmful to you.  You can also gently scratch at the surface of the shirt to see if the shirt has been polluted or contaminated in any way.

Summary:
Determine whether the stitching has been hand sewn. Look for gauntlet buttons, a few inches up past the cuffs of your shirt. Inspect the back of the shirt for a "split yoke. Check the ply count of the shirt. Look for additives in your shirt. Look for any potential allergic reactions.