I have used the same TA for all my cruises except once .TA was closed and found a smokin good deal that was only for 2 days on a long week end.
In some Canadian provinces TA's have to pay into a travel assurance fund
that covers you for TA , cruise line , airline etc failure before & during your travels.
I have now developed a relationship when I call with a cruise she doesn't have to go looking and recommending me a cruise .
I just tell her the Line , itenary , date & cabin . Then just goes out and gets me the best price. If I see a special price on line she usually can get me the same or very close.