Sustainability means different things to different people. Many people want to produce their own food but have no intention of giving up electricity or municipal water. Some strive for energy self-sufficiency but happily participate in co-ops and CSA. Some want it all ~ being totally off grid, growing 100% of their food, and making a living from the land. No one, I think, can truly be self-sufficient outside of a community that has enough resources and skilled people to produce everything needed, and for those that choose newer technologies such as solar electricity there is the need to reach out into the greater manufacturing world to get necessary components.
I'm not exactly sure what sustainability means for us. Certainly we have put in motion the procurement of local foods. We've reduced our gasoline consumption, our electricity and natural gas usage, how much water we use, and how much stuff we buy. In terms of the Riot 4 Austerity we're now at around 30% of the average American when all categories are weighted equally.
I think, perhaps more than self-sufficiency, we need a model of interdependence. Together sustainability is an achievable goal. Relocalization is happening in small pockets across the country, and even across the globe.
Anyway, we're trying to figure this out without a trust fund (no judgment ~ if you have one, great), and without raiding the HELOC. We have modest accessible savings that can help us with the small stuff, but that won't cover going off the grid or completely redoing the house in terms of windows or insulation.
The cash flow situation means smaller steps taken over a longer period of time. We've been increasing our food storage. I ordered a water purifier. We're committed to growing some food year round, rather than letting the fact that we've not yet set up large gardens be a road block. Once every couple of months we can tackle a medium-sized project, or we can wait 6 - 12 months and do a bigger project.
I finally did post on the homesteading thread. I decided that the world needs urban homesteaders every bit as much as it needs rural homesteaders.