Sometimes what's in the store just doesn't fit
One of the things I truly love is creating special something. That something special that fits your space perfectly and fills the needs you have. A quarter inch here, a few eighths there. It makes a difference because every home is different. And it's not something you can get off the showroom floor.
Depending on the style, many pieces of custom furniture can be made very economically. Custom furniture doesn't need to be expensive. If you have a space where "off the shelf" just isn't working, then custom may be the way to go.