possible rule for my own game

[Lost_Nomad]

so I have been thinking about adding a bit to some of the characters for my own game and one thing that I came up with concerns the fighter since I play a fighter in another game its always on my mind.

basically a fighter is trained for battle right? not just basic combat like a militia or whatever but this guy or girl is a career fighter. so I think that if the party is resting the Fighter should have advantage on any checks to detect enemies trying to ambush them because I think a life as a fighter would train them to be at rest but also focused and ready

what do y'all think?

[Azgeroth]

i see what your saying, but really i think this is more suited to a background. if you consider, a battalion is marching, stops and sets up camp, would all of the soldiers be responsible for keeping watch? certainly a good number would due to shift rotations, but not all.

also, considering not all fighters are soldiers (gladiators for example) i don't think it belongs to the class, perhaps as an archetype ability?? but again, I think background is better suited for this.

[Ninja_Prawn]

I don't see any reason why every fighter would be more alert than every non-fighter. This sort of thing is already present in the mechanics: you can take proficiency in Perception, you can get the Alert and Observant feats... it's easy enough to build a fighter than can spot things.

The rest is role-playing: if your fighter is a twitchy, paranoid war veteran, you should be saying things like "hang on, I want to check behind the bushes to make sure this isn't an ambush" and "I'll take first watch" and "while you're navigating and Soveliss is foraging for food, I'll keep a look out for potential threats."

[Specter]

If anything, your proposed rule would work in combat, not outside of it. If you let Fighters take the Search action as a bonus action at high levels, it shouldn't break anything.