I do this with Evernote and RememberTheMilk. In practice, an alert shows up in my task list that says "Review article XYZ" with a link. When I review it, I mark the task complete. The task will appear again after the repeat interval I selected.
To make it all work has a number of steps that may sound overwhelming, but in practice is a mouse click here and a mouse click there, once it is all set up. Here's the overview, you'll have to figure out the details of download, install, and setup for yourself:
Get a (free) account with Evernote and RememberTheMilk, if you don't have them already.
Install Evernote's Clearly in your browser. It will reformat web pages with just the main article, removing all kinds of distractions from the text.
Install Evernote's Web Clipper in your browser. For additional flexibility, install Evernote on all the platforms you use, including a desktop version.
Create a folder named "Reading" in Evernote.
Configure Clearly / Web Clipper to default to the Reading folder.
On the Evernote web site, link your Evernote Reminders to RememberTheMilk
Create a "Smart List" in RememberTheMilk that includes these filters (you may want to include more, depending on how you use RTM). You can create a separate list, or integrate it in other task lists.
status:incomplete and (dueBefore:Now OR due:Never)
You are now set up to easily add reading material to your collection of things to review, and to have reminders to review show up on a list periodically. In operation, either of these workflows will be useful:
Web Reading: An article / blog post / something on the web is something you want to review periodically. Reformat it for distraction free reading with Evernote Clearly (one click). From the Clearly display, Clip it to your Reading folder in Evernote (one click). Evernote in your browser will offer to let you edit the note. Either now, or later using another Evernote app, edit the note and add a reminder (a few mouse clicks, maybe selecting a due date if today isn't what you want). See "Make the reminder repeating" below.
PDF or other non-web files: Import the file to Evernote. There's multiple ways to do that. I most often email an attachment to a private address at Evernote which automatically loads the attachment to my account. I also use a desktop feature that lets me designate a particular folder for files I want to load to Evernote. Drop the file there, and Evernote (desktop) finds and loads it automatically. There are other methods available. Once you have the file in Evernote, edit the note containing it, move it to your Reading folder, and add a reminder. Then see the next section, "Make the reminder repeating".
Make the reminder repeating: At this point, there is a note in Evernote containing the document you want to review. The note has a reminder, with a due date, which could be today. Now go to RememberTheMilk, where you will find a task entry for the note, with a due date and containing a long and obscure URL that is a link to the web view of the note. It is most likely in your Inbox, unless you know enough about RememberTheMilk to change default configuration, in which case you probably already know the rest of this. Edit the task, change the due date if you'd like, and add a repeat interval. You can repeat at pretty much anything you can imagine: "every 90 days", "after 180 days", "every March 1", and so on.
At this point, you can open the Smart List from step 7 above, and any of these reminders that have a date in the future will not be visible. As time marches on, the task will appear on the list. When you have reviewed the material, mark the task as complete. The repeat feature will have the task show up again on schedule.
As I said, what looks like a lot of steps to set up, but once there, operation is easy. Check the smart list that includes your reading material to review regularly. Select one, and then the URL it points to. Review the material. Mark the task done, and wait for the next time.
Add new material to review by adding it to Evernote, setting a reminder, and then setting the reminder to repeat in RememberTheMilk.
Almost forgot: for new or one time reading, add a reminder but don't set a due date or repeat. Those reminders will appear in your RememberTheMilk smart list too. (That's the "due:never" in the smart list definition.)