My sister in law needs to start guessing as soon as she moves up a level from Easy. Medium she will make some guesses. And at Hard level she has to guess in pretty much every puzzle.
People need to stop thinking that 'when i hit my personal skill level cap, the puzzle then requires guessing' as if that means 'if i cannot do more without guessing, than no one else can'.
When I was playing Sudoku almost every day, I would google and study all the harder patterns to solve. You start with some of the easier such as '
cross hatching' which generally fills in a ton of squares via the process of elimination, then you move up to techniques like
X Wing and
Swordfish, etc.
I could play almost all games at expert and fiendish levels. I abandoned many games at those levels as I would never guess. But i also completed the majority of them.
The key, imo, to the harder levels is to be so diligent you never make a mistake in the early fill in squares, because if you are confident you made no mistake then you know an answer is ahead and you just need to find it. I would put puzzles down and come back to them the next day or days later with fresh eyes which often helped. And you could not vest that much time and effort if you knew you were prone to silly mistakes in the prior fill ins as you would have that doubt. Or at least, I would.
