Can i repair pants that break/wear-out in the crotch area without using a machine? Sewing Machines Parts and Sales in Los Angeles

It seems my pants have a tendency to break along the seam in the crotch area long before the rest of the pants are worn out. This applies to all kinds of fabrics and types of pants. Is there any technique i can use to fix this by hand so that i can make use of my otherwise perfectly good pants a while longer?

Since its always in a fairly obscured location it doesn’t have to be a particularly good looking repair. As long as its discrete enough not to stand out to much.