IMO, the lowest to put in is ALWAYS the amount to get the most employer match, i.e. "free money", in your case 6%. I put in 10% for 10 or more years, with a 6% match...then I moved the "extra" 4% to an outside Roth (bank debit every 2 weeks). I will say if you have a Roth option, I like that, saves tax money later very possibly...plus its more accessible with less penalties later if you need to withdraw for some reason. Get that free money for sure!