Thanks for the replies. My application is for a PCB being installed in a vehicle. The voltage is usually 13.8 volts. As I had some problems with some of my optocouplers being bad and had to replace them, I wanted to try another method (voltage divider) where you don't usually get bad resistors. I calculated 10k and 4.7k to bring it down to about 5 volts (or in my case, just under 4.5 volts). The Zener was to help maintain a max voltage of 5 volts to not damage the PIC, while the bypass cap helps to filter some of the noise in the line.

Do everyone's suggestions still stand? It seemed like a simple problem at first, but then the more I began thinking about all of the variables, I started second guessing myself. Is there anything I should change to the setup?

Thanks,
Tony