Some questions (and a french game)

I'm a french player, and, to begin, here is a review of the first "Monster of the Week" game I ran : http://www.gulix.fr/blog/?article237
I took the scenario "The Red Ghost" from the "Supernatural Adventures". I like it (second time I was running it) because of its twist about the nature of the ghost. The game went well, but I came across some "difficulties".

First, I think I asked too many rolls. At the end, one of the player (The Disciple) told me he could have marked almost fifteen experience. He wanted to test this system, and was always "helping out others". Do I need to ask my players to run "Investigate a mystery" at each location they search ? In this case, there was at least 4-5 times, for each player.

They also made extensive use of the "Use magic" move. I tried to balance it by asking components, and making nasty second effects. But they wanted to use it for many things (mask their presence, follow trace, see the past, ...). It's partially my fault, cause I didn't put limits in the beginning (I wanted a more "physical" approach).

But all the players and myself were happy of the game. And we all want to put it in motion again. Thanks !

The balancing factor for "too many" rolls is the cost of 7-9 or miss results. That's particularly the case with combat or using magic. There's a difference in style, too.

In a lot of games, you'd roll an ability or skill any time the character does something that fits in. Here, you can just say they succeed if that's what the story in the game calls for. Use your Keeper and threat moves as well as calling on the hunters to use theirs.

You do not need to roll investigate for each location - it should instead be every time the hunter is trying to find something out (e.g. asking witnesses or looking for clues). Also, if a clue is very obvious, you can just reveal it without a roll.

I wouldn't stop them from using magic all the time. But, I would make a miss on use magic very bad indeed. For example, have a rift to another dimension appear or a release an evil spirit into the world.

Thanks for the answers. I will try to find some "bad issues" to respond to magic use, according to the tone I want to give to the world.
I note these advices, and will try to put them in application !

Cool, I'm glad that was helpful. Just remember, any time a hunter misses a roll you're allowed to be really mean.