It depends on the person, and the arrangements in which it was given. My general rule of thumb is, if it's family, I give it expecting NOT to get it back......but, that's just me. If I have ever borrowed money from a good friend, or family member, I make sure to repay it. If not, it will probably stay on their mind. I know it is always in the back of my mind, especially when and if I see them out spending money, knowing they owe me. Even if you are dating the person, if it comes up again, I would decline loaning it.
when I was getting married, I paid for the rings, wedding, and honeymoon, even her dress. she was supposed to get the marriage license, but a bottle of wine made her misplace her wallet. so I had to buy it ! I'm still waiting to get my eight dollars back ( I remind her all the time)