In contrast, patches are developed on an as-needed basis to combat specific, immediate threats to our customers' security. The key thing to remember about service packs is that they are planned releases. The reason all this planning is needed is because, in our view, every customer should apply service packs as soon as possible after they're released. If we were to produce lightweight service packs at rapid intervals, administrators might judge that they were not worth the time and effort required to apply them to hundreds or thousands of machines. On the other hand, if we were to produce very large service packs at infrequent intervals, administrators might be leery of installing such a large code change.
Patches are just the opposite.
Because we can't easily change the scope and frequency of service packs, we develop patches to provide interim solutions to security issues that arise between them. As a result, there will always need to be patches. Service Packs are Comprehensive Service packs have a significantly larger scope than patches. Every service pack addresses not only security bugs, but also bugs affecting stability, performance, proper operation of product features, or other areas. In contrast, a patch is tightly focused on one and only one issue.