Peter,

Actually the code that Dimava posted will check once each second. The Timer is set using milliseconds. 1000 milliseconds = 1 second.

The Timer interval can go up to 65535 milliseconds, so if you want to you can set the interval to 60000 to check the time once each minute.

I am no expert on operating systems, but as far as using up resources, I do not think that a timer running in the background will cause any significant performance hit.

Your operating system is constantly updating system timers in the background hundreds, if not thousands of times each second anyway. So your program jumping in once each second is just another of numerous processes that are occurring.