I purchased this extension, because you loose overview very soon, even if you have only a small amount of websites to administer. What extension is installed in which version and where? SP Staging solves this problem. You have one Manager site and multiple satellite sites (or Clients, called servers). You install the manager module of SP Staging on your manager site and the server module(s) on any site you want to monitor.
Though I had a little trouble in setting up the whole system (forgive me, the documentation could be more clearly) - there is noch reason for not giving a five star rating to it. Support is very helpful an fast and solved all issues and questions short term. Glad to have purchased it.