Grocery shelves are looking a bit thin these days.It's not like the excellent toilet paper shortage of 2020; instead, it's a growing number of frustrating, hit-or-miss deficiencies this time.And shoppers are getting frustrated.We found Katie Ellis stocking up on school lunch fixings for her five children, but she says something else is missing from the grocery shelves each week."Today, it was paper plates," she said.She also could not find small bottles of water and juice drinks this week, only large bottles."Gatorade, and a lot of different juices, are missing today," she said.Other school lunch staples are also short.With the return to school, Lunchables are like gold these days.We found pizza Lunchables in one store. In another, we spotted turkey and cheese, but no pizza Lunchables.Meantime, many cleaning products remain in short supply: shopper Mahogany Wintersmith would love to find Scrubbing Bubbles spray cleaner."Just basic stuff you need for your home. They never have it. They are just out," Wintersmith said.Why so many shortages all of a sudden?It's frustrating because you never know which products you like that will be in short supply from day to day.The Wall Street Journal pointed to a variety of contributing factors:Overseas shipping bottlenecksStaff shortages at processing plantsTrucker shortagesNabisco bakers strike now, on top of everything else, threatening Oreo cookies and Ritz crackers supplies.Grocery chains are reacting as quickly as they can. Walmart says it is adding more trucks, even its ships, to bring in foreign products, and the retail giant is hiring 20,000 workers.Kroger told analysts it is building 20 automated warehouses and hiring more associates. Kroger's first robotic warehouse just opened.But in the meantime, shoppers like Debbie Caldwell say it's "very frustrating. The shelves seem to be getting smaller and smaller and smaller."And in a flashback to the summer of 2020, some stores are putting up purchase-limits signs again, limiting the amount of bottled water and other items where supplies are tight.Bottom line: Expect continued spot shortages into this winter, and plan ahead, so you don't waste your money._______________Don't Waste Your Money" is a registered trademark of Scripps Media, Inc. ("Scripps").Like" John Matarese Money on FacebookFollow John on Instagram @johnmataresemoneyFollow John on Twitter (@JohnMatarese)For more consumer news and money-saving advice, go to www.dontwasteyourmoney.com.