Couple caveats about Plan B:

Although it’s listed as being effective if taken up to 72 hours after intercourse, the further along you are in that window when you take it the less effective it is. That’s because it has inhibits ovulation - if the egg has already been released, it won’t work. That’s why it’s important to have it on hand.

It also has a weight limit. For women over that limit, it is significantly less effective. Given America’s obesity epidemic, that’s something worth knowing.