Hi Chris,

The example I wrote will maintain a 24 hour cycle as long as it's powered up but the internal oscillator only has a 1% tolerance at room temperature so it will drift. Over a period of several months you might be an hour off from where you started but you should still be getting an interval very close to 24 hours. If that's a problem then you probably should use an 8-pin PIC (12F629, 12F617, 12F635, 12F675, 12F683) and a crystal which should get you accuracy to within a minute or so per year.

Cheerful regards, Mike