My math was admittedly simple but illustrates a point. If I invest $1,000 a year for 10 years and a marginal 6% return, a fee of 0.04% is about $31, that's not enough to make a meaningful difference. Source . It's probably not worth fretting over.

> would you recommend someone roll money from an IRA (with good low ER funds) into TSP or a 401k? Why or why not?

No, because it probably wouldn't make a big difference.

But, it depends on the fees. In my experience, funds in IRAs tend to be higher than those in 401ks, and are usually much higher than 0.04%. That's why I argue that 401ks and the tsp are superior in many cases. Large employers have negotiating power to demand low fees. Individual investors don't get that same luxury. This is of course not universally true.

My only argument here is your statement that IRAs 'easily beat' a 401k. Funds in a 401K will often match or beat an IRA in terms of fees. I have both. I've had to go through this decision multiple times.