I recently had occasion to look into diapers for an elderly pet. (Moderators, I name no names and can obfuscate the species, but you will see that "widgets" won't do.) It turned out that the most highly-regarded manufacturer could, nevertheless, not be recommended-- because delivery was so slow that the buyer's pet often died before the product ever arrived.
So let that be your new benchmark, your minimum standard: If the customer dies of old age before your product is delivered, your delivery time is too slow.
:)