Good dog clothing will have some tell-tell marks in the construction. Anyone who truly understands dogs, will be aware of the things that will make dog clothing a lasting investment. Cheap construction in large sewing mills, will not result in a good quality stitching and a lasting garment. The type of stitch as well as the type of thread will largely determine how long the clothes are usable.

If you have a large dog, it is even more important to get clothes that will stand up to the pressure. Large dogs will strain the stitching much more than the smaller breeds. This is an important consideration when you look at price vs. quality.
Good dog clothes will cost more and as you buy for a larger dog, the price goes up even more.

Some things to look for specifically when you are looking to buy dog clothing.

1. Stitching should be tight and the ends should be backstitched at least 1/2 inch. This is what holds the stitching tight and will keep the fabric from ripping under stress.
2. The fabric should be hemmed properly and the edges should be either bound or fused, depending on the materials used.
3. The attachment points should be heavy buttons or Velcro. Velcro is used many times and it is easy to get your pet into and out of, but velcro can get really muddy and matted with hair. Large buttons, if sewn correctly, will give you at least as good a garment as the velcro, if you can hold Fido long enough to get the buttons fastened.

Since you are going to pay your hard earned money for these dog clothes, get quality and you will have them for a long time.