We're planning on using jpcache, but would like to use a low expiration value for the refresh rate. My question is: each time the cache of a page is generated, how much of a load is that on the server relative to simply serving the page? i.e., if the page is viewed 10 times in 10 minutes, is it worth caching the page once every ten minutes? What's a reasonable low-end expiration value and still experience load lightening?