Is this normal (20 characters)?

Often, I'll buy a pair of pants, and they'll be kind of tight, but the next size up is too big, so I buy the ones that are slightly tight. Then, I notice that the next few times I wear them, they're not tight any more, sometimes even a little big. It's not after I've washed them or anything, more like...I need to run out really quickly, and they were the nearest pair of non-pajama pants so I slip them on despite the fact that I found them strewn across a chair. XD