Question: I had my first session as Dungeon Master (DM) yesterday playing pathfinder ("First Steps In Lore" from the "Pathfinder Society" series) with a group of first-time tabletop RPG players (myself included). Overall the sessions went well, a good crash course for everyone and everyone seemed to enjoy themselves.

My question is a problem I personally had while DMing. I taught the players that they can roll for perception to check things out, finding traps and secrets, etc. The players got the idea and started saying "roll for perspection to check out the room", etc., and they found a couple of traps that way, and that's fine. The problem I had was: What do I do with all the "useless" rolls?

Most of the time they were rolling when there was nothing to find. Even on a natural 20 I kind of just described the room in more detail while saying something like "but there is nothing of interest".

Is there a better way of approaching this? Do I make something up?

I'd like to add: I would prefer my players roll their perception checks when they are actively looking. I am not a fan of the hidden-DM-rolls-for-all-perception idea.

Answer: 
When I GM, there are generally four ways a perception check plays out.

1) There is something to be discovered. If I know that there is a trap or an ambush in the room, then the player's might spot that thing. Depending on the amount of success on the perception roll, the player's may get different levels of information. Maybe they realise that there is a pit trap in the middle of the corridor. Or maybe they can just see that the floor looks weird, like it doesn't fit in with the flagstones around that spot.

2) If you have nothing interesting prepared, there might be something to be discovered. If I haven't prepared anything in the room, I'll quickly consider if there still might be something the players can discover. Are there monsters in other rooms nearby that might be heard? Tracks or other signs of activity? Murals or furniture that have hints about the history or nature of the place? Like with 1, the level of success determines amount of detail. Could be vague like a sound from the next room over that might just be the ruins crumbling, or could be something alive moving around. Or explicit, like a mural showing the ritual used to open the magically sealed door elsewhere. Or inconsequential, such as destroyed machinery that reveals this to have been a torture room.

3/4) The perception check might fail, or there might be nothing that the players can discover. In both cases my answer is something along the lines of "Well.. there doesn't ***seem*** to be anything in the room." My players quickly learn that my suggestive tone means nothing in this case. I generally find it easier to always make it sound like the group missed something interesting, instead of trying to always make it sound like there was nothing interesting. The important thing is that your reaction is the same in both cases, so the players get no clue from you.

The way I play it, perception checks are used for finding interesting stuff. I don't go into minute detail about the architecture or furniture or how the air smells, unless that detail is either useful or interesting for what it reveals. My players won't care about those minute details, and I see no reason for punishing them for looking around. I want them to look around. So they can find all the interesting stuff. And when there is no interesting stuff to find, I get it over with quickly with the simply words "Well.. there doesn't ***seem*** to be anything in the room." So we can quickly move onwards with the action.
I would say, allow a character an opportunity to roll a perception check...
And treat it as a "Gut feeling" type of thing about a room. If, they want to go in more depth into a room, treat it as a Search attempt (X amount of time at a DC of Y) and do the whole DM trick of secretly rolling for random encounters or dual perception checks (do your characters notice the guards patrolling and do the guards notice the characters searching where they shouldn't be)

However, I would distinguish between, "You don't see anything obvious..." and "There is nothing here..." -- by that, I mean, EXPLICITLY, make it obvious that additional checks are not going to find anything so don't waste time rolling.

Maybe in the first case, they failed the roll or there wasn't anything to find...but, I would definitely try to make it obvious when additional checking is not going to be productive.

Though, I agree, you should wean the players off Suggesting checks and more into describing actions/intentions...