Whether you’re washing your hair or doing laundry, chances are you use a certain amount of product each time. Dispensing shampoo onto your palm or taking a swig of mouthwash might be second nature now, but at one point you likely followed the directions on the packaging.

But how accurate are those directions? Product manufacturers stand to gain from over-consumption because it requires customers to replenish their stock more frequently. For that reason, it’s important that consumers occasionally reevaluate how much product they use. Here are eight household products with advice that may differ from the label directions.

1. SHAMPOO

Recommendation: Quarter-sized amount

According to New York dermatologist Dr. Debra Jaliman, a quarter-sized amount of shampoo is indeed appropriate. However, many shampoo bottles direct consumers to “lather and repeat as necessary.”

Fox News Channel lifestyle and parenting expert Cherie Corso believes the more consumers can eliminate chemicals in their daily lives, the better. Corso owns G2 Organics, which sells safer household items, but she believes consumers can cut back on chemicals by merely changing the way they use certain products. “Shampoos and cleaning products can be cut in half with water and you will get the same results,” Corso advises.

2. ASPIRIN

Recommendation: One or two tablets every four hours or three tablets every six hours

Over-the-counter pain relievers seem harmless, but there are side effects, especially for those taking them every day. Corso feels that too many people turn to medications instead of treating the root cause. “Most people get headaches because they're dehydrated,” Corso says. “All they need is a glass of water.”

3. LAUNDRY DETERGENT

Recommendation: Fill cap to bar one for medium loads, bar three for large loads

Detergent manufacturers direct customers on product amounts by printing bars or a line on the product’s cap. However, overuse of detergent can cause residue build-up on washing machines and clothing, leading to dingy clothes and an unpleasant smell in the basin. Cleaning expert Jolie Kerr directs consumers to never fill the cap more than one-third to one-half of the way.

4. COUGH MEDICINE

Recommendation: 20 mL every four hours

A persistent cough can be painful and annoying, especially if it’s accompanied by other symptoms. Cough medicine can provide relief, but it can bring side effects like diarrhea, drowsiness, headaches, and insomnia. Instead, Corso recommends treating a cough with a natural remedy like tea and honey.

5. MOUTHWASH

Recommendation: Rinse full strength for 30 seconds with 20 mL morning and night

Many consumers use mouthwash to eliminate the bacteria that causes bad breath. However, the American Dental Association (ADA) recommends consulting a dentist about the right type of mouthwash to use. It also shouldn’t be seen as a substitute for brushing or flossing.

6. SUNSCREEN

Recommendation: Apply generously

“Generously” is a vague term, leaving many consumers to wonder just how much sunscreen is necessary to protect themselves from sun exposure. “The standard rule is a shot glass of sunscreen for head to toe coverage,” Dr. Jaliman says. And remember to reapply every couple hours and after excessive sweating or swimming—sun damage is no joke!

7. MOISTURIZER 

Recommendation: Apply liberally

Moisturizers protect the skin against aging, replenishing moisture to prevent wrinkles. Some brands even contain protection against ultraviolet rays, keeping wearers safe from the sun in their day-to-day lives. Dr. Jaliman says the rule with moisturizer is merely to apply as needed.

8. HAIR GEL

Recommendation: Quarter-sized amount

A quarter-sized amount may be all that’s needed to provide the styling control a person needs. However, for those with finer or thicker hair, amounts may vary. Hairstylist Harry Josh recommends a nickel-sized amount for fine or medium hair and a silver dollar-sized amount for thick or curly hair.

Directions can be a great guideline, but it’s always important for consumers to use their own judgment when deciding on dosages. And with medicines, there’s no substitute for the advice of a medical professional, since recommendations can vary from one person to the next.

All images courtesy of iStock.