I've got a friend who always reminds me of her personal financial success. I'm happy for her, but sick of hearing about it. When does sharing a success finally seem like bragging?

Next time she brags about it, just tell her "I know, you told me before". If she persists, say something like "I know, you've already told me about 20 times" or maybe "so you keep saying". If that doesn't get through to her, tell her to shut the f*** up. Lol:)

After the first conversation, & even that should be very brief    

The second time it is brought up it's bragging.  Tell her you know and you are happy

for her, so she doesn't have to keep telling you about it.  Smile while you're telling her.

maybe you should ask them to teach you how to do it so you could do it too

Immediately.

It begins immediately.

The next time she starts?  YAWN and keep yawning until she shuts UP.  And if she does not shut up, walk away. 

That isn't a friend, that is a dysfunctional, insecure person who is only listening to herself brag.

I agree, Sharonna.