Patterns can save time when used correctly, or they can slow a model rebuild time if not. The advantage of feature patterns is that they can be used as a source for other patterns at the assembly level (feature—driven patterns). Patterns can also be used as a source to add fasteners to assembly using Smart Fasteners. This has the advantage of faster rebuild times as pattern controls the position of the fasteners instead of mates.
Avoid patterning on top of other patterns. Instead, make a single pattern with all the features.
Move big patterns as far down the FeatureManager design tree as possible. This allows the other features to be built first and also allows the pattern to be suppressed without worrying about parent/child relationships.