Pack-It folders are the only way I go IMHO. Ive done the space saver bags and was unimpressed. One or two ripped on like the 1st or 2nd trip making them useless and the clothes were kind of wrinkled. I could have gotten the same results with the jumbo ziplock bags for a fraction of the cost.
Campor or REI sell the folders. Im sure there are other places online also. They keep everything nice and neat and your stuff doesnt slosh around inside the suitcase. I turned my neighbor on to them and he's buying more.
One other tip get a mesh laundry bag to hang in the closet to serve a clothes hamper.
Maybe pack an extra collapsable duffle bag to throw all the dirty clothes in coming home saving space in your suitcase for stuff you've bought on the trip.
CCL Inspiration 09
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CCL Miracle Southern '08
RCCL Enchantment of the Seas Western '07
PCL Caribbean Princess Eastern '05
RCCL Explorer of the Seas Western '05
RCCL Explorer of the Seas Eastern '04
CCL Destiny Southern '01
CCL Sensation Eastern '94
CCL Ecstacy Western '92
CCL Jubilee Eastern '90