How should I set my lead time?

The lead time should be the days from now until when your orders will be ready for your customers.
For example, if you want an extra month worth of stock, you should set the lead time to your supplier’s lead time plus an extra 30 days.
If you have an internal process that needs to be followed once orders arrive before they are ready to be sold to your customers, you should also account for this in the lead time.