This is a great question.
Ideally, you should have as many Lead Magnets, as you do have types of content.
So if you have content about insomnia, you should have a Lead Magnet for that.
If you also have content about stress, then you should create a stress-specific Lead Magnet, for that.
And so on.
This is easier said than done, however.
When you first start out you will probably just want to get a Lead Magnet up and running, fast.
One is better than none.
But eventually you will want to customize things even more.
You are going to have a more effective Lead Magnet, if it is tailored specifically to the type of audience (and problem), that viewers to a certain page attracts.
Now let's move onto the Next Step...