If the cost of the 1 forgotten essential item plus shipping is greater than the cost of 5 extras, then I'd rather always buy 5 extras.
If the cost of the 1 forgotten essential item plus shipping is less than the cost of 5 extras, then I'd rather always forget 1 thing.
If budget is no consideration, then always 5 extras. Final
answer!
Aspirations: She seeks wool and flax, considers a field and buys it, girds herself with strength, opens her mouth with wisdom, and does him good all the days of her life. (pieces of Proverbs 31, NKJV)