I would agree in general with everything said so far on this but it's
actually more complicated than this; but still very simple.

In general, if your fermentation vessel is not closed or poorly
sealed, once the wine is close to done fermenting you risk oxidation.

Transfer of that wine is always recommended, especially if it's
white. Bring everything over, it doesn't matter if it's from juice,
grapes, honey or fruit wine. Get it under airlock now and keep it
that way. Don't top up yet. That way you are assured you will remove
all of the oxygen when the fermentation completes. That is the safest
way to remove the risk of oxidation.

Once it stops bubbling; check the gravity over a few days and see if
it's still dropping. (A better test is Clinitest; see if the Residual
Sugar is 0.2% or less. If so, it's done and now you let it settle and
rack; never transfer again.

If you are fermenting in sealed containers a transfer will not be
needed, just racking.

I agreed with everything said about timing; time is not important,
sediment is. Gross lees are a bit dangerous. The lees from an
initial ferment may decompose if left alone. Gross lees can be a
problem, you need to either remove them or check the wine very
regularly, as in every few days if you feel a need to leave the wine
on them.

Fine lees on the other hand, stirred, can impart a 'butteriness' to
the wine and that can be nice in a Chardonnay or good Chenin, it's a
little odd in a Riesling. It's not often done in reds, but a mediocre
Pinot may be made more interesting this way. If you want to leave
wine on the gross lees, you need to stir it and check it. Once that
first rack removes the gross lees, the fine lees are not quite as
problematic in my experience.


Joe