One issue to be addressed when considering a cruise is where to start from.
Cruising from a UK port has advantages and drawbacks.
A recent cruise from Southampton to the Canary Islands took three days at sea to reach our first port of call: Funchal Madeira. The return leg from Lisbon took two. That's quite a chunk from a two-week holiday, and to be honest the time spent in Lisbon was disappointingly short. Some will opine that every minute on board is part of the experience to be enjoyed and I wouldn't argue with that. I would assert that waking up in a different port every day is an attraction, too, and the more of that the better.
On the other hand there's effectively no luggage limit if you're not flying. A 2-week cruise with themed and formal nights has a hefty luggage demand and flying guests will invariably be up to the limit. And if you're bringing lots of presents back... don't get me started on that one.
Even sailing from the UK there is still the matter of reaching your departure port - with all your luggage. You can fly from the north of England to Southampton, which gives you the worst of both worlds, or go by the shuttle coaches arranged by cruise companies. These rarely pick up near home so you still have the same problem on a smaller scale. We invariably end up driving there, staying overnight and leaving our car by arrangement at the hotel. (Hilton Hotel, Chilworth, I'll give you a plug here so long as you promise to prompt your guests to book the with-taxi-to-the-port option when they book to keep their costs down.)
There is another issue likely to cost you days from your holiday. The ship we travelled on seems to have an endemic problem with Norovirus. (That's winter vomiting virus to you, and an attack is very unpleasant, if short-lived.) Not short-lived is the 48-hour quarantine period. They'll confine you to your cabin if you get sick, even if it's just a tummy upset, so every aspect of hygiene deserves attention. Wash hands often, use the germicidal gels and be very picky about what you eat and drink. Use your own pen to sign the tabs and use your pen as a prodder for the elevator buttons. They promise a voucher for discount on your next cruise is you are confined, but we haven't seen it yet. Perhaps you have to ask. I'll give them to the end of the month before I begin to push the issue.
The third issue which is close to my heart is that of disabled access. Some ports put on shuttle buses if the ship is very far from the port entrance or resort: others do not. Similarly cruise lines, who should always do so in my opinion. Even when they are provided they might not run all the time, so beware. And cruise lines please remember: "Only 500 metres to the port gates.." means exactly the same as "A full half-kilometre to the gates and them some." Would you say that to a guest with mobility problems without offering help?