Does Excel offer a way to alert you of a change in data?

I am responsible for the tracking and maintenance of our fleet of vehicles.
I would like to know if there is ANY way to set-up a spreadsheet so that
every 3 months or 3,000 miles, Excel will let me know that the vehicle is
ready for Preventative Maintenance service.

Any suggestions? I hope I'm not the only one who has every been curious
about this.

I have already tried to work a bit with conditional formatting but not with
much success.