Use of speed brakes in flight

[colsie]

Hello all. I think this might be my first post here.

So a tiny bit about me first of all. I am called Colin. I am 15 live in Glasgow, Scotland. And love planes.

I have a question regarding the use of speed brakes in flight and on approach.

What are the real life limitations apart from speed for not using speed brake in flight?

Is there any point in which it is forbidden as so to speak to release and use the spoiler in flight?

Is it really advisable to use speed brakes in flight unless it is absolutely necessary?

Thanks,
Colin