If you want to know how frequently your Visualforce pages are accessed, you just have to run a simple query on VisualforceAccessMetrics:
SELECT ApexPageId,DailyPageViewCount,Id,MetricsDate FROM VisualforceAccessMetrics
That query will return stats from the latest 90 days
Page views are tallied the day after the page is viewed, and each VisualforceAccessMetrics object is removed after 90 days.
But BEWARE, that query could return deleted pages. To fix that, let’s tweak the query to:
SELECT Id, Markup, Name, NamespacePrefix FROM ApexPage WHERE Id IN (SELECT ApexPageId FROM VisualforceAccessMetrics)
Now the query will return only existing pages.