My luck has been up and down with rare drops. I had a devil of a time getting cockatrice (the better part of a week, couple hours a day). Next on my list was Mindflayer, and I literally got it on the first drop!!
Bomb came next, and I procured that summon in less than a half-hour. My good luck streak slowly degenerated after that. I next went on a Tail hunt. The pink tails went smooth if slow, at about the rate you'd expect for a low drop rate. This trend continued for the rest of the tails until my final three: one black and two red.
I think I the black tail took the better part of two days. The reds were worse by a large margin. The first tail took me weeks! I don't remember how many weeks, because I got frustrated and stopped playing for a few months. When I came back to FFIV, it took another week before my first red tail drop. The next one came five days later. I am counting my blessings. --- Slow down, Gandhi, you're killing 'em