Am I required to use MRP?
The short answer is yes. Time to Shipment MRP is the core element in DBA's demand-driven, just in time manufacturing architecture and can't be replaced with alternate planning methods.
Just in time manufacturing requires a standard Lead Days for procurement time against all P items, a standard Job Days for production time against all M items,, and a consistent To Order or Stocking order policy for lead time contribution against all items. Stocking order policy items require supply pipeline settings to replenish stock at demand-driven intervals. Demand-driven jobs and purchase orders are generated by MRP on a daily basis to assure that materials are on hand by job planned start dates.
This demand-driven, just in time architecture is not compatible with alternative planning methods. Use the item planning settings as designed and you will get good results, whether you make to order or to stock or have standard or customized products. On the other hand, if you bypass or co-opt item settings or bypass MRP generation with manual planning, you will get very poor results.
