Welcome to YT!
For us, it started as a functional thing since Tuffy used to travel with my husband & I (semi trucking doggie!) so in the cooler climates he'd wear clothes. In snowy climates we'd layer his clothing when needed to. When Bella came along she was just too cute NOT to dress up.
These days, the dogs & I are in Florida where it's too durn hot for clothes most of the time. We'll be moving to Indiana soon though so that we can see Dad more than a week every 3-4 months.
As for how to get them used to clothing, be sure to start with something lightweight but well fitted. Not too loose, not too tight. Be sure your pup can move freely, especially around the shoulder/top of leg area. If you have a boy you may need to shorten certain things so he doesn't dirty it when he pees.
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