Peachy -- I don't think prodding DS every five minutes 24/7 so that neither of us got any sleep for the first year is recommended either, which is what would have happened otherwise (he was a PFB, after all... I think I'll be a bit saner this time round).
We had DS in with us for the first 9 months, as well.
In our case
(a) DS had whooping cough from 2 weeks old, so would have coughing fits and turn blue followed by a long (not 20 seconds, but seemed endless) pause before he could take his next breath. Given that on one occasion (not when he was asleep, actually, but when I was holding him) he didn't start breathing again until I dangled him upside down and gave him a slap I liked the reassurance of knowing each time he had a coughing fit at night (which he'd sleep through, astonishingly) (that is, he'd sleep through the coughing fit, not sleep through the night. Oh nononononono ) that he was still breathing, and
(b) when he wasn't coughing he'd sleep so deeply that the only way I could tell he was breathing without the monitor was to prod him.
Now the monitors he was on in hospital -- those went off all the bleeding time for no reason (I think I had literally 2 hours sleep in the 72 hours he was in for whooping cough ).