Manufacturers tweak laundry detergent formulas often. Here’s what you need to know.

Are you pro powders? Prefer pods? Loyal to liquids? When it comes to doing laundry, people are particular!

But did you know that some manufacturers tweak their laundry detergent formulas as often as every year—and some several times a year?

Since your detergent may have changed, the experts at Consumer Reports test dozens of them yearly to find the ones that clean best.

“Our tests are extremely tough; even the best detergents can’t remove every stain completely so it’s really about getting one that works for what you are typically laundering and whether you routinely have heavily soiled clothes,” explained Consumer Reports Home Editor Perry Santanachote.

Consumer Reports’ testers launder fabric swatches soaked with blood, body oil, chocolate, coffee, dirt, grass, and salad dressing. The lighter the stain after washing, the better the detergent scores on cleaning performance.

Testers also checked out an alternative to typical detergents—laundry sheets—made of concentrated laundry detergent and held together by a resin and dissolvable paper. And they are also free of plastic packaging.

“The laundry sheets as a group didn’t perform as well as liquids and pods in our tests,” said Santanachote. “However, if your laundry isn’t heavily soiled, and you’re looking for a more sustainable laundry routine -- these could be a good option.”

Tide Plus Ultra Stain Release and Persil ProClean Stain Fighter tackled dirt and body oil, as well as tougher stains like grass and blood.

But if grass and blood stains aren’t a routine occurrence in your home and you’re looking for a better value, Consumer Reports says to consider Kirkland Signature Ultra Clean Liquid from Costco.

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If convenience is key, the Power Pods from Tide earned top scores among the pods. However, that convenience costs more and pods have other downsides.

“Pods can be dangerous, especially in households with cognitively impaired adults or young children who might accidentally ingest them,” Santanachote warned.

Another reason to stick with liquid detergents: They can also work double duty as pretreaters for stains, which means one less product you need to buy.

None of the detergents in Consumer Reports’ tests were stellar at removing coffee stains, so if you spill, its experts say your best chances of removing the stain are to act especially fast by flushing the fabric from the back with cold water and then applying a pretreat or detergent.

Think you know everything about doing your laundry? Not so fast -- check out five things Consumer Reports’ laundry expert would never do. Watch the “laundry don’ts” below: