Some people just can't/don't know how to pack - my mum for one! My dad said it was being in the Army that taught him to pack and travel light. I bless him and the fact he taught me his packing methods every time I pack for the family holidays.If we were doing an ex-UK roundtrip sailing then I wouldn't hesitate to take a bit more, maybe an extra tux and some additional footwear - men's footwear does seem heavy, even shoes that are supposed to be lightweight - my black formal shoes for evenings weigh the same as three pairs of my wife's strappy shoes! Maybe an extra pair of shorts and a couple more casual shirts to save too many "repeats" and it also gets around the need to do some "holiday laundry" while onboard. On homeport sailings from So'ton we would take take two good-sized cases each.
Our short cruising history is a combination of fly-cruises and ex-UK so we have learned to pack accordingly. The more tricky ones are mixed-climate cruises - autumn departures from the UK to warmer climates - requiring cool weather clothes for the first 2/3 days before the warmer weather starts ...... and then if you are on a T/Atl assuming you are flying home from Florida or Caribbean, you have strict luggage allowances to keep within. Oh, the joys of travelling.