I know in Robert Jasiek’s books though, e.g. his Endgame book 3 Accurate Local Analysis, he shows positions where you might not know if a move is sente but you can estimate the size of the mistake by counting it as gote or sente. It might be off by a few points.

So then I guess it’s worth trying to think of what sente means in counting.

In Antti’s book it’s written like:

a move that ‘forces a response from the opponent’ and ‘that can be responded to with out taking a loss’.

The example in Antti’s book goes like this:

What’s the value of the move at A? Is A sente?

If you do the whole gote move calculation you find that the expected territory of the whole position is 2, but if black is also prepared to always answer A, like it’s sente, then black doesn’t take a loss. They move from a position of value 2 to a position of value 2. They can expect a minimum of 2 points locally.

So in the above you can see the “without taking a loss part” and the “forces a response” is kind of a hypothesis. It has to be at the stage of the game where a 1 point move is actually the biggest, because if not, you’d estimate the above as 1 point gote and then play the bigger move the opponent missed.

There’s another example with two stones to be saved /captured as well, but the whole global context is that it might be sente as long as there isn’t a bigger move elsewhere. In the course of a game, because of the types of moves available, you might not always get to play “your sente” because of having to take a bigger move first and your opponent getting to play it as reverse sente as the next biggest move.