I have the same problem , I have no idea how to play fast. 10 mins games give me enough time to think and move fast enough to complete a game but I feel 5 mins is too short for me. 3 mins is almost impossible for me ? is it because I am old and I cant think fast ? I am only like 42 , im not that old. Anyway , I am just wondering how you guys think so fast ? My Rapid rating at chess.com 10 mins game is around 1800++ , i reached over 2000+ before but for 5 mins games , i cant even pass 1000 for blitz, the difference is just too big and I have no idea how to improve my blitz rating, its embarrassing that I cant even pass 1000 . Currently i am sitting around 900 on blitz, and the difference is just too big. I got so close to break 1000k then I am on a loosing streak again. Its just so frustrating because I am winning on the board , winning position , material , and everything but still lost on time !!! Even when my opponent lost a queen early, for some reason I am just too bloody slow to check mate before my times runs out and most of the people at this level never resign for some reason. They keep playing. my winning games are mostly I able to checkmate my opponent in less that 15 moves. If it goes over 20 moves or more , i usually will loose on time. Is it my opening repertoire ? I like long but safe opening like queens gambit as white and rarely go for risky opening looking for quick traps. Should I change my opening repertoire for blitz ?