Ok, but in this case the contractor should make at least 2x as much the in-house staff, considering they're bringing all their own tools, paying for their own health insurance, paying their own taxes, and having a more flexible schedule.
And then there's the question of why hire a contractor in the first place if you already have a strong team of devs — why not just hire another full-timer? Most likely you're having trouble filling out your team or filling a crucial role. That would probably be worth a little extra to you.
Plus, there are tons of companies out there who don't need a full dev team of a dozen people, but know they could benefit a lot from hiring contractors for 3 months at a time for one-off projects. These companies are more than willing to pay a little extra to get a job done well on short notice.
And then there's the question of why hire a contractor in the first place if you already have a strong team of devs — why not just hire another full-timer? Most likely you're having trouble filling out your team or filling a crucial role. That would probably be worth a little extra to you.
Plus, there are tons of companies out there who don't need a full dev team of a dozen people, but know they could benefit a lot from hiring contractors for 3 months at a time for one-off projects. These companies are more than willing to pay a little extra to get a job done well on short notice.