How many bundles needed with a closure?
8-14inches------ 2 bundles,
16-22inch --------3 bundles
24-30inch---------4 bundles
Above is the suggestions , but you can put more or less according your own need

How many bundles do you need with a frontal?
Frontals are from ear to ear ,13*4 or 13*6 lace frontal will covers more spaces than closure or leave out, so the hair amount you need will be less.

Below is the suggestion for the amount
10-18inches -----2 bundles
18-24inch -------3 bundles
26-30inch -------3 or 4 bundles
Usually , one full head need different lengths of bundles , for example , 22” wig , you need 18inch frontal and 18 20 22 bundles to match . but you can adjust it as your own need . you can also match like 20 20 20 .