Most places that do alterations can do repair. But someone who is very good at repair is worth extra. Good repairs are strong. And they'll see weak areas needing repair before a hole starts, which might require patching.

Buy that cashmere sweater and repair it. I've got two over 20 years old, one pair of jeans over 5 years old I wear so often they got crotch holes in them, easily and authentically repaired.