Also as a former travel agent, I'll concur with 784caroline's observations.
After I have selected a particular cruise by my own on-line research, I still book through an agent with whom I used to work.
1) She almost always comes across a special deal (the trip I'm about to leave on she waved some magic wand and I was eventually upgraded five decks and five verandah categories for no additional charge!) even after I've booked.
2) She knows exactly what I want in terms of accommodations and Cruise Connection transfers; I never have to tell her again, unless I want something different.
3) She always sends me a bottle or two of wine!
4) She's always available in an emergency and can cope with virtually any "catastrophe!"
And, I always, always buy insurance. When I was an agent, I saw too many instances where clients lost a bundle of money because they had to cancel late and didn't have insurance.
SWR