You don’t want the garment to shrink so much that it feels drastically different from when they first tried it on to when they put it on after it is washed. You want your customers to be able to count on the fit enough to make a purchasing decision that they won’t regret after they take the garment out of the wash.
This is why the unofficial industry standard is that more than 5% shrinkage is unacceptable. More than that and there is too big a discrepancy between pre and post-wash. Less than 5% and ideally less than 3% is a tolerable amount of shrinkage. (To put these percentages into context, 5% length shrinkage would equal about 1 ½” shrinkage on a pant inseam or 1”-1 ¼” shrinkage in body length for a top.)
Most customers understand that new clothes will probably shrink a bit in the wash. You as the brand can even make a note on the product page about how much shrinkage to expect the fabric has a shrinkage percentage on the higher end. You don’t want any surprises for yourself or for your customers.