Another use for milk jugs--poke a bunch of tiny holes, fill with water, and bury next to plants you want to keep watered for a few days. 

My church women save their egg cartons for me & I take them to oldest DD to use with her laying hens. She often has eggs to share with her church, so she needs an ongoing supply, since those ones don't come back. I reuse the 8 oz yogurt container to freeze fresh fruit, like strawberries, blackberries or peaches, stewed rhubarb, or currant juice. I write what is inside on the top, then when I am ready to make jam, I pull out the containers. One container = 1 cup, which makes the measuring easy & fast. I use the plastic grocery bags for trash can liners, & to share produce from the garden with others. Last year I used doubled grocery bags (mine, youngest DD + her roommates, & oldest DD)  to haul gravel from my local freecycle & craigslist to my oldest DD for her driveway every time I visited from March to November. I found the ones from our local Macey's & Kmart could be used twice, but the Smith's & Albertson's were only good for one trip.

Those tiny jars are great for holding screws and other small hardware that you need to keep sorted. Some people reuse baby food jars for this purpose. One tip I heard is to nail the lid of the jar to the underside of a shelf, then screw the jar onto it. Keeps all the jars neatly organized and you can't lose the lids.

We use powdered milk mostly, so we seldom have milk jugs. Those jugs that do come into our house tend to get reused for storing emergency water supplies. I like to keep at least a week's supply on hand. I started doing this in 1999 when people were predicting Y2K disasters. Then Y2K turned out to be a big nothing--but about a week after that, there was a flood at the local water works and the water was unusable for several days. So I was mighty glad I had all that stored-up water on hand.

I have not tried starting seeds in egg cartons. My dad starts his in cut-off sections of PVC pipe, and it occurred to me that toilet paper tubes would probably serve the same purpose--so now I am saving all our TP tubes to start next year's seedlings in. I'm not sure whether to plant them tube and all or make a "pusher" of some kind to pop the seedlings out of the tubes. I'm not sure how fast the cardboard would break down in the garden.

Plastic deli containers are great for storing leftovers, except that you can't reheat them in the microwave. So we use them mostly in the freezer for things like cooked beans and homemade stock.

My folks use quart-sized applesauce jars for mixing up powdered milk. I tried it for a while, but I found the lids didn't fit that snugly, so now I use a Tupperware bottle. What I'd really love is an old-fashioned milk bottle (for the irony), but I think most of them didn't come with reusable tops.

Most of our other containers just get recycled. For a while we were saving all kinds of containers thinking we'd find a way to re-use them, but at some point we realized we had as many empty jars stored up as we were ever likely to use, and we couldn't spare any more space for them.

 I am re-using the plastic container in which nurseries sell plants, to fill with my garden dirt & plant some maple seeds & heirloom apricot pits.  Hope to grow some to use in the windbreaks for DD's 10 acres.  We already re-use some of the larger ones to haul over the "volunteer" elm trees that litter my garden thanks to the big elm across the fence.I've had the seeds for a year or so; just didnt' think about growing my own.

 The part with the milk boxes is an amazing advice. I'll try that one for sure. Thank you very much.

A few of the ways I've reused packaging:-

• Yogurt/ cottage cheese tubs were painted by the kids as a craft project for use as small plant pots
• Plastic grocery bags for lining trash cans, packing shoes when travelling, "stuffing" for some fabric Christmas ornaments I made one year
• Jars, cottage cheese tubs etc are used to sort small craft supplies.   DD uses egg cartons to sort her beads when she's working on jewelry projects
• Save any and all boxes for packaging gifts.  Use newsprint and make homemade wrapping paper to wrap gifts!
• Baby wipe containers have been used to store crayons, scissors and other craft tools
• Unusually shaped glass jars have become vases - the foliage disguises the fact that it's a jar
• Where possible I buy my laundry detergent in buckets - between DH's messy work and various household jobs, we never seem to have enough buckets
• The children have made gliders from reused styrofoam trays (not the ones that contained meat)
• DD goes through lots of Gatorade with her swim training.  We save Gatorade and other similar bottles - half-fill with water and store in the freezer.  We live in the Caribbean - year round hot temperatures, so we need to drink a lot.  Top up a frozen bottle with water when we hit the road - no need to buy drinks when we leave home
• Ziploc bags - washed and reused.  I prefer to buy freezer bags as they stand up better to frequent reuse.
• Save shampoo and conditioner bottles for my dad's workshop - he'd buy the wood glue in gallon sized bottles (much cheaper) and pour glue into
• Save pump bottles from liquid soap etc.  We use one for dishwashing liquid, and the kids were taught to use one squirt to wash their plate, glass etc (we have no dishwasher; we have a wash-as-you-go policy as DH and I can't STAND to see mountains of dirty dishes, which will happen pretty quickly with 4 kids)
• Another pump bottle use - I have one that is filled with diluted baby shampoo, which I use to remove eye makeup

I'm not much of a gardener, but I just remembered something that my dad used to do - he'd get hold off 100 lbs sacks and created windbreaks to shield newly planted citrus trees from the wind.

I'm re-using a wooden crate that originally held popcorn in a display set up by my DIL's mother, that DIL used to transport "the beloved bunny" several times. I washed it well & set it out in the sunshine during the summer to disinfect & remove any smells, & now I am using it to store & display my handmade goat milk soaps.  If we decide to sell at the local Farmer's Market next year, all I need to do is print a large sticker with the herd name, & place it on the crate on either end, over the popcorn logo. 

I also have a metal sleigh that originally held soaps& lotions, that youngest DD bought to use the contents for "roommate" presents last Christmas.I was considering painting the sleigh black - right now it is gold - & putting the herd name on it. If I fill it halfway with shredded paper fill from brownpaper grocery bags, it would make a nice display item for the soaps as well, & should hold around 8-10 soaps nicely displayed.  For the holiday season,however, it will be filled with pinecones I have gathered, & sit by the front door.

I have a totally trashed dresser drawer full of USB's, chargers, and remotes.  I'm contemplating getting a beer case and a cardboard box from the convenience store, covering the beer box with giftwrap, and making dividers from the cardboard box and giftwrapping them as well.