Typically the only requirements are waiting X days until you get the next event. The code may be used at any time. Kali needs to be above certain levels for some of Lucy's events.
thanks for the response Runey, the code definitely has to be used then. You don't get them without it?
That's right, you cannot see all of Lucy's story without the code.
Out of pure curiousity, is there a reson it is locked behind the code? Why is it not a part of the game. Not complaining just asking hehe.
Thanks for the help Runey. Really loving the game. Best Renpy project I've played