Quoted from Bryan_Kelly:Experienced tapers sand off about 10% of what they put on. Homeowners that have no idea what they're doing, sand off about 75%.
I work as an electrician but have done several drywall jobs. thin coats are better than thick, use wide knives 12" for butt joints 6-8" for corners. I only sand once at the end (maybe a little spot sanding in between) but after each coat scrape any ridges and high spots with a dry knife. This makes much less dust.
As TheLaw said more thin coats is ultimately better in the end.