The benefits of a sharing economy are reducing waste and expense, but also, depending on who you're sharing with, getting better quality items. I do very little shopping because my family members get rid of things and offer them to me. I can frequently get a lot of older items that are higher quality than some new things I can buy. I've gotten several cotton or wool sweaters from family, whereas many that I can buy are acrylic, which is not nearly as sustainable as something natural like wool.
I pass this on by helping out my brother. I was able to give him some extra things that I had accumulated so they wouldn't be wasted (they were just collecting dust), and he was able to save some money and not purchase new things that would require more resources. I was even able to salvage two perfectly good cabinets from my old job that were going to be thrown out that he can use for years to come. I always offer around if I have something that I'll be getting rid of (my mom has gotten clothes from me this way too!), and my family does the same, which means we don't always have to buy new things. It's also nice to know you get family heirlooms, even if it's just a blender or a old department store sweater from the nineties--it means more just coming from someone you know! And often older things are better constructed because they were built to last, so it works out pretty well if you end up with them.
I think an important part of a sharing economy is letting go of perfection. Yes, this table may be dented and nicked on the legs, but it was free from a family member, and it suits my needs and it works with what I have, so do I really need a new one instead? I think letting go of the need for everything to be shiny new and carefully cultivated in an 'image' is really central to helping a sharing economy feel more natural. Now, you don't have to have extremely clashing items just because you feel you have to keep a closed loop in your sharing circle, but if that red crockpot your cousin is giving you doesn't match your blue kitchen, does it really matter if you know you'll use the appliance? My philosophy is if it works and I don't hate it, and I think I'll use it, then I'll keep it/accept it from someone else. No sharing economy is perfect (sometimes people just don't have your size or that specific thing you need), it's always worth a try to see if you can arrange a swap or share. You may be surprised!