Patternitis

One problem for which there is no pattern is the unnecessary or inappropriate use of patterns. This has earned patterns a bad name in some quarters. Because pattern solutions are neat, it is tempting to apply them wherever you see a fit, whether they truly fulfill a need or not.

The eXtreme Programming (XP) methodology offers a couple of principles that might apply here. The first is "You aren't going to need it" (often abbreviated to YAGNI). This is generally applied to application features, but it also makes sense for patterns.

When I build large environments in PHP, I tend to split my application into layers, separating application logic from presentation and persistence layers. I use all sorts of core and enterprise patterns in conjunction with one another.