What is the effect of using a wider seam allowance on pattern pieces?

Using a wider seam allowance on pattern pieces facilitates more fitting adjustments. This is particularly beneficial during the construction of garments, as it provides additional fabric at the seams that can be taken in or let out as needed. Having that extra fabric allows for modifications to the fit of the garment after it has been initially constructed, which is a crucial aspect of tailoring and customizing clothing to fit the wearer's body shape.

In contrast, narrower seam allowances might restrict alteration possibilities, making it challenging to achieve the desired fit without additional pieces of fabric. The versatility offered by wider seam allowances can significantly enhance the overall fitting process, ultimately leading to better-fitting and more comfortable garments.