I finish in 6 minutes. I don't feel like explaining in detail for the tenth time, as I've talked about it many times. I rarely spend the full 6 minutes (I think, on average, it's 5). I strategize on the fly, based on my opponent's moves, and use my time as efficiently as possible, never waiting for it to run out completely. And I advise all beginners to play on 6 minutes if they want to improve their skills.
P.S. Now Nagán will come and write a multi-volume lecture about the harm of playing on 6 minutes :D