When I dropped my Logitech K200 keyboard last year, one of its feet snapped off, and the foot couldn't be glued back together. I measured its unbroken partner, replicated the design in 3D Studio Max, and printed the resulting model in PLA on my Prusa Mk2. I printed it in the cheapest plastic I had, bright translucent green, expecting that I'd have to iterate a couple of times. It fitted perfectly first time! I decided to keep the green version - it tickles me to have such an obviously-printed part that works so well. I think it took me about two or three hours to complete this, from breakage to replacement. I think that a digital caliper is one of the most important parts of a 3D printerer's toolkit - it's invaluable for working out how big small stuff should be.