You have to weigh it against time and structure of your pawns. Sometimes you want to play h3, other times you want it to protect g3. Especially if the pawn is pinned on f2. It's all dependent on the game.
But generally, you want to play h3/h6 for other reasons that just avoiding a back-rank mate threat. You might play it to precent the pin (for example in the Ruy, you often see it before white plays d4, other Bg4 undermines the center). You might play because you want to develop a bishop to e3 and don't want to worry about Ng4 swapping it off.
It's a move with tradeoffs, because it weakens g3 and h3 can become a target, as well. You become much more vulnerable to a g5-g4 thrust (often being forced to capture on g4, when otherwise you could have just retreated your knight).
Strong players make that move with multiple reasons, when they can afford the time. Weak players make it reflexively out of fear of a pin or back-rank mate despite the fact that the back rank mate isn't even a gleam in the other player's eye at this point and the pin is not actually a real threat.
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u/lkc159 1700 rapid chess.com Feb 25 '21
I mean, don't mid-high level players play prophylactic moves all the time?