you can get 2 days wear out of a pair of shorts, maybe 3 - on some days you will be in and out of your shorts and into your bathing suit more than anything else. I pack a t-shirt or a tank/sleevless shirt for each day - never know what the weather will be. 2 swimsuits for a 7 day cruise. Clean shirt each night for the men/boys. I pack sundressess for myself - just so easy to slip on with a pair of flat sandals and a light cardigan sweater. 3pairs of docker's type or cargo pants for the men/boys. I usually pack myself a pair of khakis also. 1suit - 2 dress shirt/ties, 1 pr. dress shoes- for the men/boys. 2 Formal outfits for the ladies.
actually Harry had a great tip a bit ago about using Ziploc bags for socks and underwear, pack socks in one bag, get all the air out of it ( sit on it if you have to) and just throw it in your suitcase, same goes for the underwear. Same idea as spacebags but a heck of alot cheaper.