Version:           4.2 rc1 (using 4.2.00 (KDE 4.2.0) "release 83.1", KDE:KDE4:Factory:Desktop / openSUSE_11.1)
Compiler:          gcc
OS:                Linux (i686) release 2.6.27.7-9-default

In the KOrganizer's To-do list, recurring To-dos do not remind each time before the recurring time is reached, but only once before the "Due" time of the entry is reached.
Recurring To-dos seem to suffere a little bit of design problems, but this I would call a bug.
I would expect that reminders of recurring To-dos (and events) would act each time according to the recurrence interval defined by default (or as a default option, allowing to switch to one-time reminders, but this would be a wishlist entry).
The same problem was already reported for KDE3:
http://bugs.kde.org/show_bug.cgi?id=140551