How many times can you change villagers' greetings?

[Barney]

I'm just curious, really - once you give them a custom greeting, is that it, or will they suggest changing it again after a while?

 

[Ananas Dragon]

I'm just curious, really - once you give them a custom greeting, is that it, or will they suggest changing it again after a while?

They will probably suggest changing it after a while, I believe it's unlimited