I am planning to liquidate my holdings in two non-Vanguard funds and consolidate in VTSAX. This will all be done inside a Vanguard Roth IRA, so commissions will only be due for the two sell orders. Should I practice dollar-cost averaging while investing this money in VTSAX, or reinvest everything as soon as I can?
Dollar cost averaging is a fancy name someone came up with to say "Invest all of the time". I would not bother with spreading out purchases. If the market is too expensive right now ...so what? The items you sell will bring top dollar. The fund you buy will cost top dollar. It all evens out.
You could sell your assets and just sit on cash, but that would require knowing when the next market drop is coming..which no one knows. Also, it never really is cash; it goes into a money market fund which is not guaranteed. I would rather own companies(VSTAX) and collect the dividend.
There are been many tests about invest all the money immediately and average it out during a period of time.
The results favor to invest the lump sum immediately, so your money starts to work and produce income with dividends. Cash don't produce any income.