I have on many occasions, however I only brew ales, ciders and wines. I'm sure there would be issues with lagers. But as long as everything is sanitary, and it is properly sealed with plenty of CO2, you should be good. I did a very dark ale back in October. Let it sit on the primary for about 2 months, and then in the keg for about 2 more. Took it over to a buddy's for a welcome home party for a friend and it was a hit. Keg was empty within just a few hours. So in my opinion, depending on what you're putting in it. Yeah, it should be good to go.