When looking in your fridge, do you ever wonder if certain items are still good?

"When in doubt, throw it out" is a wise piece of advice when it comes to food products. But when groceries are so expensive, you don't want to be wasteful. AOL Health has some good tips on what to keep and what to toss:

• Milk, butter and dairy. The date stamped on the product is a good guide. (Pay attention to whether the date is a "sell by" date or an expiration date.) Hard cheeses keep longer than soft and shredded cheese. Toss any dairy product that has been unrefrigerated for more than four hours. And, use your sense of smell -- if dairy is starting to smell off, then throw it out.
• Meat and fish. Fresh fish and meats last only one to two days in the refrigerator, though some (ham, steak, roasts and lunch meats) can last up to five days. Freezing meat can extend its shelf life.
• Condiments. Replace opened bottles of ketchup after six months. Mayo should be replaced in two to three months.

Check out the full article for more tips.