I admit, we treat our dog like a person some times. Most of the clothes we buy are good, but I often wonder if I'm buying it just for our sake, or does a sweater really help the dog in the winter.
Other clothes, like his polo shirt, help dress him up and give him a personality.
One problem with the clothing is how it is cut. We bought a sweater made for a dog, but it covered his privates...not good when you are taking a dog out for a walk to relieve himself!
Another issue is where, or even if, there is a hole cut out so that we can put the sweater/shirt on him over his harness, and still be able to clip his leash on through the cut out in the shirt. Some don't have the cut out, some are just in places that don't work out too well.
I've also seen, but have not tried, booties for a dog. I'm not sure if my hyper pup would even let me put those things on his feet. It's probably easier for me just to wipe off his feet after a walk in the wet grass or snow, then it is to put those things on his feet every time we go outside. A lot of whether it is practical for a dog to wear clothing depends on the type of dog, and if the pet is patient enough to let you put the clothing on him in the first place.
I'm also amazed at how the market for pet clothes continues to grow. A big retail chain has a little section for dog clothes. There are pet botiques and specialty stores. I was in Atlantic City and saw specialty pet shops in the casino. It's a huge market which keeps growing.