Lol, no-one wants to give OP a straight answer xp.
The answer is 120-350 hours. Unless you go way overboard with your builds and then you can add a 0. But you're probably wondering how long the game lasts if you go through all the content at a steady clip without taking too much time out for ♥♥♥♥♥♥♥ around. In which case you're looking at 250-350 hours. Less than 250 is if you only build what you ABSOLUTELY need, but building a good setup for yourself is a big part of the game so almost everyone takes at least 250 hours to reach the very end.