"I ALSO pack my large carry-on bag, IN the suitcase."

I have a collapsible fold-up duffel bag that is large enough to carry clothes and toiletries for a three night stay that I use for short weekend trips, as a carry on piece of luggage.

When empty, folded and zipped up, it takes up only 10" by 10" by 2" thick space inside another carry on piece of luggage. It is very useful sometimes!

Bob