At what age should you stop using a baby breathing monitor

[maltesers]

At what age should you stop using a baby breathing monitor. My sister has a 2 yr old and still uses hers. It must be hard to stop when you are anxious bout your little one, especially when you conceived after years and years of infertility treatment. Just wonder if this is excessive.. think so myself. personally if i had had one i would have stoppped after the baby was 6 months or so . any opinions? ?

I got my monitor when ds2 was 4 months old and felt like a different person, just happier that if something did happen I would know about it asap and have the chance to do something IYKWIM. He used it until he went into a bed- 2.9. Dd is using it now, however I'm MUCH more relaxed this time around.