All festivals have a sort of "one and done" feel to them. I only go when they are particularly meaningful to the sims I am playing at the time. I do keep them in mind a little when I plan out my rotations, so the sims who have chickens are played the week of the chicken and egg judging fair, I had a celebrity sim recently get married at the romance festival because fans would have been annoying on extended wedding events, geeks like geek con and mischief focused sims like the Humor and Hijinks, etc.
I have never been able to catch most of the Island Living events when they are happening, and the turtle hatching appears to happen when I am playing any household other than the one that actually helped clean up Sulani.
Mostly I only manage to enjoy most of them by leaving multiple in-game weeks, and preferably real world months, between my visits to each one.