It is good to reuse as much as possible,but do not re-use plastic bottles indefinately since the chemicals in them can break down and "leach" into what you're drinking out of them over time.Another good reason to eschew plastic containers and go back to glass.

I'll never reuse a disposable item primarily for health reasons. Having said that, I don't consider some common intentionally reusable items as disposables, such as grocery bags. Those will always get a second purposeful use.

Well, I keep some glass jars to use for storing stuff, and I reuse plastic grocery bags for carrying stuff or as trash bags, but I'm not nearly as effective at this as my mom is. She reuses lightly-used paper towels. She would wipe off a fairly clean counter with one, rinse it, then lay it out to dry. I just don't think I can be THAT persistant.