Growing up we had a Crisco can on the stove with recycled grease that was used for weeks. It had about five inches of sludge at the bottom. (Yuck!) When I moved out on my own I continued this habit until I realized that the weird taste in fried foods was rancid oil. So I started straining and refrigerating used oil. Made a big difference. Now I may reuse a couple of times before discarding. Anyone else?