It depends on where in Birmingham that you live, but generally I'd say it could take anything between 1 hour and 1 hour 30 minutes just to get there. There's usually more traffic on the way back on the motorway. I know people who do commute there, and it's definitely doable, but you're looking more at 2-3 hours to get there AND back. Once you actually get off at junction 15, the journey isn't too bad and it's. a pretty simple drive.