With the internet providing consumers the convenience of 24-hour access to retailers, many shoppers—particularly younger ones—are abandoning their real-world shopping carts to complete their purchases online, a new study suggests.

Zebra Technologies Corp., a retail solutions provider, surveyed approximately 4,811 shoppers, 1,100 retail workers and 435 retail executives to determine what shoppers across the globe look for when shopping in-store and online. The study suggests that the digital age has given consumers a multitude of options, and even when a customer enters a brick-and-mortar store, they may still be tempted by the convenience and accessibility of online shopping.

There are a number of reasons why consumers choose to visit a brick-and-mortar store rather than shop online in the first place:

• 53% want to experience the product

• 46% believe the items will be more readily available in the store

• 41% want the item immediately

On the other hand, those who prefer to shop online tend to do so for free shipping (45%), product availability (43%) and online-only offers (43%).

Even so, physical stores don’t appear to be meeting the needs of some shoppers. The No. 1 reason that shoppers leave stores without making a purchase is because the item they wanted was out of stock. With online availability, many shoppers find it more convenient to buy what they are looking for online rather than wait for the store to get new inventory.

Younger consumers are most likely to do this, as 75% of millennials and 53% of Gen X shoppers reported leaving a brick-and-mortar store without making a purchase and later buying a product online for this reason. Baby boomers were less likely to turn to the internet, as only 26% reported buying an out-of-stock item online instead. According to Pew Research, millennials are between the ages of 23 and 38, Gen Xers are between 39 and 54 and baby boomers are between 55 and 73.

Aside from an item being out-of-stock, the remaining top five reasons that consumers leave stores empty-handed are:

• They didn’t like the product choices

• They found a better deal elsewhere

• In-store pricing differed from online pricing

• The checkout line was too long

For retailers losing business because of long lines, the study offered a glimmer of hope. Consumers are increasingly embracing self-checkout lines rather than waiting for a customer service representative to check them out. Among survey respondents, 40% of shoppers said they had used self-checkout lines in the last six months, and 86% said they were comfortable with the technology.

More than half of consumers — 58% — even said they believe self-checkout availability improves the customer experience. Younger consumers were particularly enthusiastic about the technology, with 70% of millennials saying that self-checkout lines improve the shopping experience.

The breadth of options available both in-store and online puts consumers in control when it comes to choosing the shopping experience that works best for them. Not only can you use the internet to compare prices and often take advantage of free shipping, but you might also find it beneficial to use certain credit cards that are more suited for online shopping than others.