Why do you use a 5/8 inch seam for sewing clothing?

Answer 1

very simple, take this as an example( you're walking down the street, you slip, catch your balance but your rear is out due to a split or tear, you take off your pant and discover that it will not mend right .) Why? no seam!
5/8" seam gives you access toward a better chance of hold on your material while sewing without altering it to much, plus without a seam, the stitch would'nt last long, always tearing.

Answer 2

Years ago when the first patterns were mass made, someone decided that 5/8 inch seams on all patterns would be the standard. This was suppose to make it easier to use different brands of patterns. If you will notice a lot of the new pattern makers no longer hold to this practice. Some patterns today do not have a seam allowance at all. A big oops when you try on garment you just made without reading the directions! Word of warning, always read directions BEFORE you cut pattern out or sew a stitch.

Answer 3

A 5/8 seam gives you enough to anchor the cloth, and support the stress of a garment. If your pattern calls for the standard 5/8 seam and you want the finished garment to be the size it is supposed to, you need to follow the directions.

I know this seems "duh" but my normally intelligent sister had a hard time figuring this one out. Hope this answers the question you were asking.