RedmineReminderEmails will just send out notices to everyone. I would suggest making this a personal setting on My account page (like other notifications), allowing to set up the following:

• send/don't send ticket reminders (checkbox);
• frequency (daily/weekly/custom); can be done like in Hudson - a pure text input allowing cron syntax, defaulting to "0 8 * * *" (daily at 8am);
• period before the Due/Start date to send out reminders - just like the days switch;
• tickets to process(two multiselect listboxes - Trackers and Statuses).
• use only Due or only Start date, or both (checkboxes).

Do we have anything cron-like internally?