I've been confused by those who front load at the beginning of the year. It implies they have been sitting on cash at the end of the previous year. So while it sounds awesome to max out an IRA in January, it means you much have idle cash sitting around, right?
My approach is to start the year with all the tax advantaged stuff (401k, IRA, Roth, 529) lined up with automatic contributions to max out by years end. Every time my checking account exceeds about 6k I sweep the excess into the brokerage without delay.
I don't see why maximizing money in the market at all times isn't the optimum strategy?