Demon of the First Circle limitations

Demon of the First Circle or any of the Demon spells seems ripe for exploitation. I’m wondering how other storytellers have dealt with this issue.

I’m worried because of the ease of summoning, and the length the demon will serve you. The way I read the rules there is nothing preventing a sorcerer from summoning one demon every night. The risk of failing Int + Occult vs the demons resolve is also very small. Spend willpower and a stunt, and you’re almost guaranteed to succeed. That is before taking into consideration that most sorcerers will have high int and occult, and possibly an excellency to boost the roll if they feel like it. Once summoned the demon is your slave for a year and a day.

Given the system, it feels like most sorcerers should be surrounded by a small army of demons to do their bidding.

How have other storytellers dealt with this issue? Is there anything from e3 or the other editions that can be used as a guide to reduce the exploitability of the summon spells?