Where did you run across that rule? It is incorrect.
I'd like to know if it's correct to say "I haven't been going out in the evening for ages". The rule on the use of the continuous form would prevent its use in negative sentences but it doesn't sound wrong to my ear. Thanks for your answer
Welcome to the forum, whiterose.
Your sentence is just fine.
I don't like it. It's a bit better with the plural "evenings".
I don't like it with "for ages" on the end.
"I haven't been
goingout in the evening for ages." This works for me.
"It's been ages since I went out in the evenings."
"I've been staying at home in the evenings for ages."