Susan,

"Would you recommend the same for investors in the accumulation phase and for those preparing to enter the withdrawal phase?"

I see absolutely no reason to NOT do this over one's whole investment lifetime.  Let's discuss this a bit on this GLORIOUS Sunday morning.

Here is the idea.  Actually, two ideas.  Perhaps three.

1) Given that the total return of a portfolio, percentage wise, is the sum of the percentage yield of the portfolio and the percentage change in the NAV, it seems more logical to invest in funds that have a high percentage yield, rather then low, or zero, 'growth' funds.  That is, I would prefer to invest in a fund that throws off a 10% yield then one that is expected to grow 10% per year.  This is the idea that yield is much less risky then growth.

2) Tied to 1, the growth in value of one's portfolio occurs both whenever NAVs increase AND whenever the number of shares owned increases.  During accumulation, you continue to contribute to your portfolio, purchasing more shares, but the income thrown off by your portfolio also purchases more shares.  In 1) above, prior to withdrawing, you are adding that 10% income generated by your portfolio back into your portfolio, so the number of shares owned is increasing by that same 10%/year.  This is the old 'assume all dividends are reinvested' definition of total return.

3) Moving to a higher yield portfolio, at retirement, although not all that difficult, can be traumatic.  Being in that mindset for a number of years prior to retirement means that you are quite comfortable with it.  That is, if you assume that you want your retirement portfolio to yield 6%, in order to support a 6% real, inflation adjusted rate of withdrawal, you (in your case!) have 15 years to morph into such a portfolio, such a mindset, such a cash management strategy, from your current 3% yield portfolio.

"When do you recommend . . . ."

I try not to ever recomment anything!  Except to think about things and draw your own conclusions.  In fact, I wish I had done some of this thinking 20-30 years ago!

"As noted by DG, it controls my risk (my SD) by trimming those funds that have outperformed the others and it also allows me to take my profits off the table."

A while back, I started a thread dealing with this exact subject (yield focused investing during accumulation.)  IMO, by focusing on yield, and not NAV, you free yourself from the psychological effects of volitility.  That is, if you look at your accumulation phase of life as the buildup of the yield income thrown off by your portfolio, and NOT on the value of your portfolio, you are much better off, specifically because that thought carrys through to the retirement phase of your life.

That is, if you manage your portfolio at that 6% yield for several years prior to retirement, at some point, you can comfortably start spending that 6%, rather then reinvesting it.  Or 4%.  Or whatever you need.

As an example, during accumulation, 'accumulate' into whatever stock, bond, or fund that you wish, until the monthly distribution from the fund is some target amount, say $100 (or $300/quarter, $1200/year).  Then go on to another stock, bond, or fund.  Take all distributions as cash, and reinvest back into whatever stock, bond, or fund is below that target.  If a stock, bond, or fund increases it's distribution, trim back down to the target amount.

What you will find is that you will end up putting $12,000 into a 10% yield stock, only $8,000 in a 15% yield stock (or fund, like ADVDX), but $50,000 into a traditional 2.4% yield value equity fund.  The actual stock/bond 'allocation' you end up with can be anything, as can the total weighted yield of your portfolio.

And there will be no need to rebalance, for any of the typical reasons!