I'm assuming you work in a domain environment for this, so why not implement some login script logic to do this.
We have a service that ever 30 days requests new information from the end user. We run a check to see when it was last updated, and then if it was greater than 30 days past, we through up a webpage requesting the data. It works pretty well for our needs.
Could something like that work for you?
You could also do a runonce type thing to do this, but I doubt it would do what you are looking for...
good luck