Plenty of Valentine’s Day shoppers will use smartphones to help them with their purchases. But how they’ll do it varies pretty widely, according to a National Retail Federation (NRF) survey conducted by Prosper Insights & Analytics, a business intelligence company.

Not surprisingly, age matters. According to the data, among buyers ages 18 to 24, nearly 78 percent of smartphone owners plan to use their phones in some way to research or make purchases. But that number falls to 56.5 percent for shoppers ages 35 to 44—and all the way down to 16.3 percent for shoppers ages 65 and older.

Across all age groups, the most common way to use smartphones is for researching products.

The NRF reports that 30.5 percent of smartphone owners will do just that, while 17.3 percent will actually buy something with their phones. Others (19.4 percent) will use their phones to check a brick-and-mortar store’s location, hours or directions; in-store product availability (12.6 percent); or to redeem coupons (13.3 percent).

Mobile payments still lag behind all of those uses. In fact, just 4.3 percent of smartphone owners said they would use their devices at the check-out counter, a practice most common among shoppers ages 25 to 34 (7 percent).

Overall, fewer shoppers will leave home at all this month, a trend that keeps growing. NRF found that 27.9 percent of shoppers will buy online this Valentine’s Day—up from 25.1 percent last year and 16.3 percent in 2010.