Sustainability seems to be a term that is used at different scales for policies for large businesses right down to individuals doing small things around the house. What does sustainability mean in these two different contexts?
I don't think it's as simple as two contexts. Just taking "sustainable" in the sense used by environmentalists, corporate "sustainability policy" covers everything from the goals of an organic farming co-op through to the greenwash applied by the nuclear industry. These days almost every company has a sustainability policy, just as they have a policy against sexual harassment and an equal opportunity policy (even the Catholic Church has them). Similarly, at a personal level sustainability covers the range from eco-survivalists to a billionaire telling the media that they run one of their private jets on biofuel.
But broadly, personal sustainability means someone is trying to move towards using only renewable resources in their personal life and minimising the amount of resources they consume. There are so many ways of doing this, and our current consumption is so high that most people who have internet access have a huge range of choices for living more sustainably. This site is full of examples so I won't go further into that.
Corporate sustainability policies can be broadly divided in those designed to make the company look better, and ones that are simply the goals of the owners written down. In between are policies written by smart accountants (ie, going green to save money), and those pushed by people within the organisation who are not entirely focussed on the "amoral money making" aspect of corporate lore. But one aspect of sustainability is not getting prosecuted for breaking the law or persecuted for violating the expectations of the company owners. So there's a limit - you're not going to see "Beyond Petroleum" getting out of the oil business regardless of their marketing slogans.
"Sustainability Policies" often operate at the easy end of that scale and tap into the enthusiasm of their staff. I've worked for a 30k+ employee company that had "green teams" made up of volunteers, and those teams produced policy proposals for all sorts of little changes, and when they were accepted all the teams worked to get people in the company to accept and comply with the policies. It's hard but important work, there's a lot of inertia in companies and it's very hard to be "that one guy who prints double sided" in a department. That kind of cultural change is important.
The same companies often have top-down sustainability policies too. They'll have a "VP of Green" or something similar who has enough power to push for bigger changes. From them you get "this company only buys 100% post-consumer recycled paper" and so on, which means someone has gone out and found suppliers, verified the products, made sure the required quantities can be supplied and so on, then done a budget and gone to the board to say "it will cost/save $X to change". Then they put it in the annual report and do press releases, which is why verification is so important - they really don't want the follow-up to that press release to be a demolition of some of the claims in it.
At the even-more-greenwash level, companies also engage in "pure marketing" sustainability operations. They'll put a 10kW wind turbine on the top of their corporate headquarters so everyone can see it, even though the top of a skyscraper is a stupid place to put one. They'll rename themselves "Great Environmentalists" instead of "General Electric" and trumpet stuff like putting PV panels on top of their nuclear reactors. Then a couple of years later go back to being General Electric and hope the little boost in "green credibility" they got sticks around.
Ӎσᶎ summed up what corporate sustainability is about. I want to try a different angle.
On one hand, at all scales the basic question is the same: What goes into your system (stuff, energy), what comes out (stuff, waste), where does is all come from and go to? What does this mean for sustainability? What can I change (choosing different inputs, avoiding some outputs) to improve sustainability? How much do I, do we care?
Now, on a personal scale (you, your household or familiy, the group of friends with whom you travel/have a soccer club/share a makerspace ...) it's all about sharing the enthusiasm for improving sustainability and finding ways to changea and improve the same. You don't have toanalyze avery change in light of monetary costs. Maybe you'll look at the cost and benefit of changing lightbulbs to more efficient ones, but you probably won't put a money value on the time you spend separating waste.
On a moneymaking scale, the entitiy (big or small) has to do this. Every additional hour of working time will have to be justified. That's why, even if there are well meaning people within a company, the policies that get implemented are typically the ones that cost nothing or bring a public relations boost - as described in Ӎσᶎ answer.
A company that does not make a profit, it not sustainable regardless of how little damage it does.
However a individual can decide to use options that cost a lot more then what other individuals are doing.
Thats say company "a" dose 10 “units of damage” while making the product,
Company b could choose.