There is no definitive answer to how many days it takes to lose the yellow heart on Snapchat. It depends on how often you and your friend snap each other and other people. The more snaps you exchange with each other, the longer you can keep the yellow heart emoji. The less snaps you exchange with each other, the faster you can lose the yellow heart emoji.
According to some users, it can take anywhere from 2 days to 2 weeks to lose the yellow heart on Snapchat if you stop snapping each other or snap more with someone else. However, this may vary depending on your snapping activity and frequency. If you want to avoid losing the yellow heart emoji on Snapchat, you need to snap your #1 best friend every day and make sure they do the same with you.