Do you need to start? Should you hold off? Hmmmm.
Why are you feeding, and what are trying to achieve?
Early splitting, queen rearing, are two items that come to mind. Even feeding for a lack of stores. But you do not really say. So it's hard to say when for you to start.
If your attempting to shower your bees with affection, and wanting to find something to spend money on, and think that you automatically need to do this, then anytime is a good time. Many go this route, fill the brood chamber to the point that the queen has no place to lay, and thus full spring production never really is achieved. And then there are those that feed and bring on a swarm season much earlier and stronger than needed and end up losing half their bees right before the main flow.
Keep in mind, in nature, the bees eat their way up to the top of the brood chamber. In spring, when the flow starts, the queen has a huge amount of comb below her to lay in. The bees naturally eat a good percentage of the honey to allow the room for expansion. Yes, starvation is always something to guard against. But the hive should of eaten 75% of the honey stores by the time natural pollen and nectar starts, so the queen has a large area to lay. You should not feed to the point that the hive comes out of winter with as much stores as they went into winter with.
So why are you feeding?