Of every question federal employees ask me in their last five years before retirement, this one shows up the most: “Should I just stay in an L Fund, or should I move my TSP to something I manage myself?”

It’s the right question. It’s also the wrong question.

It’s the right question because the difference between the right and wrong answer here, compounded over a 25-year retirement, is genuinely the difference between “comfortable” and “careful.” It’s the wrong question because the way most people ask it — L Fund or self-directed?— is a binary, and the actual answer is rarely binary.

I want to give you the framework I use when a federal employee sits down across from me with this question. Then I’ll tell you what I see most often.

First, a brief diagnosis of the L Funds.

The L Funds are not bad. I want to say that clearly because the loudest voices on the internet have made it sound like they are. The L Funds do exactly what they are designed to do: they hold a diversified mix of the underlying TSP funds (G, F, C, S, and I), and they glide that mix toward more conservative allocations as you approach your target date.

For a federal employee who is decades from retirement, who does not want to think about allocation, and who is unlikely to change their mix under pressure, an L Fund is almost certainly the right answer. Almost nobody beats “set it and forget it” with their own emotions over 30 years.

The honest critiques of the L Funds in the last five years before retirement are different, and there are essentially three of them:

  1. The glide path is generic. It assumes you have nothing else in your retirement picture. Most federal employees do — a defined benefit pension (FERS annuity), Social Security (or the FERS supplement), and often a survivor annuity election. The presence of those guaranteed streams changes how much risk your TSP can carry, and the L Fund doesn’t know they exist.
  2. The glide path is one-dimensional. It moves down a stock/bond ratio line. It doesn’t reposition you for sequence-of-returns risk— the specific risk that the market crashes in the first few years of your withdrawals.
  3. The L Fund doesn’t make a withdrawal plan. It makes a holding plan. Once you retire, what do you sell first? In what order? At what tax cost? The L Fund doesn’t have an opinion on any of that.

So what does “self-directed” really mean?

When someone says they want to go “self-directed,” they usually mean one of three things, and it helps to know which:

1. Custom allocation inside TSP.

You build your own mix of G, F, C, S, and I — instead of letting the L Fund choose. This is the lowest-friction path and it keeps every dollar inside TSP with its very low expense ratios. It’s also the path that gets the least credit. The TSP’s underlying funds are some of the cheapest, cleanest index funds in the entire industry.

2. TSP plus the Mutual Fund Window.

The TSP added a Mutual Fund Window that lets you invest a portion of your TSP balance in outside mutual funds. The flexibility comes with fees and limits. It is rarely the right solution to a problem that could be solved by being more thoughtful with the five core funds.

3. Rolling out of TSP to an IRA.

This is what most people actually mean when they say “self-directed.” You take your TSP balance, roll it to a Traditional IRA (and any Roth balance to a Roth IRA), and manage it outside the TSP system. The benefits are real: more investment choices, the ability to do partial Roth conversions, more control over withdrawals, and access to strategies (like single-life or beneficiary IRA structures) that TSP doesn’t cleanly support.

The trade-offs are also real:

  • You leave behind some of the lowest-cost index exposure available.
  • You give up the G Fund — which has no perfect outside-the-government equivalent.
  • You add a layer of fees (advisor, custodial, fund) that needs to be earned.
  • You sometimes lose access to the spousal consent and survivor protections that TSP’s default rules provide.

The diagnostic questions that actually matter.

Before I tell anyone whether to stay in the L Fund or move to a self-directed strategy, I ask the same five questions:

  1. What does your guaranteed income look like at retirement? FERS annuity plus the supplement, plus Social Security at whatever age you take it, plus any survivor benefit. The more of your spending needs are covered by guaranteed income, the more aggressive your TSP can be.
  2. What are your first three years of withdrawals going to look like? Not in dollars — in sourcing. If the answer is “sell whatever’s up,” you don’t have a plan, you have an instinct.
  3. What is your Roth balance? Roth dollars are different dollars. They give you tax flexibility and IRMAA flexibility that traditional dollars do not. The L Fund treats them the same. A real plan does not.
  4. What is your behavior under stress? The most expensive thing you can do in retirement is to sell stocks in March 2020. The second most expensive thing is to not have been in stocks at all because of what might happen in some future March 2020. The honest answer to this question matters more than any spreadsheet.
  5. What does your spouse understand about all of this? If one of you is the “money person” and one of you isn’t, a self-directed strategy that depends on your ongoing attention is a strategy that fails the day you stop being able to give it that attention.

What I see most often.

The cleanest path for many federal employees in their last five years is not, in my experience, “L Fund forever” or “roll everything to an IRA the day you retire.” It’s usually some version of:

  • Stay in TSP through retirement to take advantage of its costs and the G Fund.
  • Move from a single L Fund into a deliberately chosen custom mix of G, C, S, I (and sometimes F) that reflects your real retirement income picture, not the generic glide path.
  • Build a cash and G-Fund buffer covering the first two to three years of planned withdrawals, so a bad market doesn’t force you to sell equities at the wrong moment.
  • Revisit the question of a partial or full IRA rollover afterretirement, when your tax picture, RMD timeline, and Roth conversion strategy are visible to you in a way they aren’t today.

That is not as exciting as “roll it all out and we’ll beat the market.” It is, in my experience, the path that actually beats most peers’ outcomes — because it solves the right problem.