Pattern-based IR rewriting through the greedy pattern rewriter and the dialect conversion framework is widely used and one of the core mechanisms of MLIR. This talk will touch upon the parts of their APIs that have evolved/changed over the last years. The main part of the talk is a set of best practices that programmers can follow when designing pattern-based rewrites. Finally, this talk will briefly touch upon a new, simpler dialect conversion driver (without pattern rollback and automatic materializations) that is currently in development.