We explicitly ask people to include their needs in this. They are people, they have needs - ignoring that is stupid, in my opinion. If we have someone on staff who is contributing greatly to the company but has high mortgage payments, and I pay them less because I have this other person who is contributing the same but has much lower monthly costs, and I pay the first the same as the second, I will lose the first because they can't afford to keep this job.
The best answer here would be to pay the two equal employees the same amount. The responsible one can save, or treat him/herself, or whatever. Paying irresponsible people more is dangerous for your company and your employees. I spent years on the pointy end of that stick. It was a really shitty situation; I knew that the guy "needed" a lot more money than I did, because he had a gaggle of kids, a nice house in an exclusive neighborhood, a bunch of cars, etc, while I live in a modest house, owned my car outright, and kept my expenses low. The worst part about my resentment was that I felt bad about feeling it; I denied to myself that I even felt it, because I really didn't feel that it was fair to deny this guy the ability to feed and pamper his kids, keep his house, etc. So, I worked hard, kept my head down, made about a third of what he did, and bottled up and denied my resentment for years. I'm still trying to repair the damage.
So, that was long-winded and just an anecdote, but seriously, be careful with treating people of roughly equal value differently because one of them needs more money than the other one. It can work out poorly.
The best answer here would be to pay the two equal employees the same amount. The responsible one can save, or treat him/herself, or whatever. Paying irresponsible people more is dangerous for your company and your employees. I spent years on the pointy end of that stick. It was a really shitty situation; I knew that the guy "needed" a lot more money than I did, because he had a gaggle of kids, a nice house in an exclusive neighborhood, a bunch of cars, etc, while I live in a modest house, owned my car outright, and kept my expenses low. The worst part about my resentment was that I felt bad about feeling it; I denied to myself that I even felt it, because I really didn't feel that it was fair to deny this guy the ability to feed and pamper his kids, keep his house, etc. So, I worked hard, kept my head down, made about a third of what he did, and bottled up and denied my resentment for years. I'm still trying to repair the damage.
So, that was long-winded and just an anecdote, but seriously, be careful with treating people of roughly equal value differently because one of them needs more money than the other one. It can work out poorly.