How do you fix "Allowed memory size exhausted"?

An Allowed memory size of 134217728 bytes exhausted almost always means too much data loaded into memory at once, usually Model::all() on a big table, an unbounded collection, or eager-loading that fans out. We replace it with chunk(), cursor(), or lazy collections, fix any N+1 queries feeding the leak, and only raise memory_limit as a last resort. The fix ships with a test on a representative dataset.