Depends upon how long you are out on a trip, and often you can do laundry.
First, (especially if you have girls).... they CANNOT bring everything. Even when our kids were little and still camping with us, we planned 1 change of clothes every 3 days, and then it was laundry time. When we had our pop-up, we had to do it this way. My daughter hated it, but she survived. She also had to be VERY selective what she took.
Now we have a much, much larger trailer, and no kids. It's just the 2 of us. Now we pack 1 set of clothes for each day of the trip. (7 nights ... 7 pair of underware.... etc.)
We did the laundry routine up until about 2 years ago and then we finally realized.... why in the world are we doing laundry when we now have space! So we changed the way we pack now.
Still.... 3 days of cloths, and then plan on laundry time! It's about the only way to save space unless you can put a carrier on the top of your truck or trailer.