- Dryer Sheets. I reuse my Bounce dryer sheets until they become extremely limp. Usually after the first use, I will use two per load. Another clue (at least in the wintertime) for when I need to finally toss them is when the clothes come out of the dryer all static-y (is that a word?)
- Zip-top bags. For most uses, I use freezer zip-top bags. They are heavier and stand up to repeated hand washing. I only toss them once they have become so worn as to be unusable or have held raw meat (especially chicken). When using them for raw meat (marinating chicken, freezing meat, etc.), I try to use ones that have already been used at least once. The good folks who make Ziploc will advise you against reuse ("it's just not safe"), but I've never had a problem with them.
I'm sure I will think of more down the line. If there are things you reuse, let me know.