Why do my new clothes expand when I wear them?

Is there a way to permanantly make your clothes smaller (without taking them in). When my pants are straight out of the dryer the fit really nice but throught the day they expand a little, so I dont want to have to take them in, will washing them in hot water help?
Thanks!

you want to be careful they dont shrink (like become shorter... that happened to a couple of my sweaters and now the sleeves are too short)

buy one size smaller

the size smaller doesnt fit me...its really TOO tight! Like I cant even close the zipper!!

ah!! well you could always do like my son and change 3 times a day xxx just kidding lol

depends on the material as well... are they the stretchy kind?

no, not stretchy, well a little bit but not too much.
thanks for the answers btw

Any kind of stretchy jeans will expand during the day. When you are buying your jeans pull on them and see if they give any. If they do then you really don't want them.

Be careful using hot water to wash your clothes. You can cause the colors to fade and actually damage some materials.

Buy the pants that are part spandex, that way, they won't stretch out too much by end of day