Force pages to compile
When a page is served for the first time after it has been published, Sitefinity CMS generates the markup for that page and then it passes it to ASP.NET engine for compilation. Then ASP.NET compiles the page in an assembly that is stored in a temporary folder. Then the actual page instance is created from the compiled assembly and subsequent request are served faster, because the steps for generating the markup and compilation are skipped. The compiled assembly is persistent between application restarts, but it will be invalidated and recompiled, if the page is changed and republished or, if for some reason, the ASP.NET assembly cache is cleared.
RECOMMENDATION: You can create an external service, which periodically browses the site. This way it will force any not compiled page to compile.